UC-NRLF 


LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 


~,  DtOLOGY 

Class  LIBRARY 

G 


WORKS  BY  T.  MITCHELL  PRUDDEN,  M.D. 

The  Story  of  the  Bacteria,  and  Their 
Relations  to  Health  and  Disease 

Second  Edition,  Revised  and  Enlarged.    i6mo, 
Cloth  «         .         .         .         .         net,  75  cents 

"It  is  written  in  clear,  concise  sentences,  without  any 
effort  at  display,  and  can  be  read  with  profit  and  enjoyed 
by  any  intelligent  reader  as  well  as  by  the  most  scientific 
physician/ ' —  Chicago  Inter- Ocean. 

Dust  and  Its  Dangers 

Second    Edition,     Illustrated.      i6mo,    Cloth, 

net,  75  cents 

"It  is  in  one  sense  an  alarmist  book,  but  it  alarms  in  a 
proper  direction,  and  performs  a  service  that  cannot  be  over- 
valued. .  .  .  The  book  is  to  be  warmly  commended,  and 
should  attract  general  attention." — Boston  Gazette. 

Drinking-Water  and  Ice  Supplies,  and 
Their  Relations  to  Health  and  Disease 

i6mo,  Cloth,  Illustrated       .         .         net,  75  cents 

"  Dr.  Prudden's  little  book  is  crammed  with  information 
— practical  information — which  to  thousands  of  families  would 
be  worth,  if  duly  read  and  heeded,  far  more  than  money." 
— Hartford  Times. 

G.  P.  PUTNAM'S  SONS 

LONDON  NEW  YORK 


DUST  AND  ITS  DANGERS 


BY 


T.  MITCHELL  PRUDDEN,  M.D. 

AUTHOR  OF   "  THE   STORY  OF  THE   BACTERIA,"    "  THE   GREAT 
AMERICAN    PLATEAU,"   ETC. 


SECOND  EDITION^   ILLUSTRATED 


G.  P.  PUTNAM'S  SONS 

NEW   YORK    AND    LONDON 

Tfmicfeerbocfeer  press 

1910 


(^  IT  10  I 

T7 

H  10 

BIOLOGY 


COPYRIGHT  1890 

BY 
T.  MITCHELL  PRUDDEN 

COPYRIGHT  igio 

BY 

T.  MITCHELL  PRUDDEN 
(For  Second  Edition) 


ttbe  fmicfterbocfccr  preee,  flew  £orK 


PREFACE. 

THIS  little  book  has  been  written  with  the 
purpose  of  informing  people,  in  simple 
language,  what  the  real  danger  is  of  acquiring 
serious  disease — especially  consumption — by 
means  of  dust-ladf  *i  air,  and  how  this  danger 
may  be  avoided. 

It  is  an  unpleasant  subject ;  but  it  is  one 
which  every  one  must  know  something  about  if 
he  would  avoid  such  physical  ills  as  are  much 
more  serious  drawbacks  to  comfortable  living 
than  are  the  temporary  mental  disquietudes 
which  this  book  is  designed  to  inflict  upon  its 
readers. 

T.  M.  P. 


207118 


NOTE  TO  SECOND  EDITION. 

THE  revision  of  the  text  for  this  second 
edition  covers  those  phases  of  the  sub- 
ject upon  which  new  light  has  been  thrown 
during  the  last  two  decades.  But  the  general 
character  of  the  book — a  plea  for  clean  air — 
remains  unchanged. 

T.  M.  P. 


CONTENTS 


CHAPTER  PAGE 

I.— THE  NATURE  OF  DUST  IN  GENERAL  i 
II. — THE  LIVING  ELEMENTS  OF  DUST  ;  WHAT  THEY  ARE 

AND  WHERE  THEY  COME  FROM         ....  7 

III. — How  THE  LIVING  ELEMENTS  OF  DUST  ARE  STUDIED    .  n 

IV. — THE  MICRO-ORGANISMS  OF  OUT-OF-DOORS  DUST         .  20 

V. — THE  MICRO-ORGANISMS  OF  IN-DOORS  DUST         .        .  27 

VI. — THE  SAFEGUARDS  OF  THE  BODY  AGAINST  INHALED 

DUST 36 

VII. — THE  REAL  SIGNIFICANCE  OF  DUST  IN  ITS  RELATION 

TO  DISEASE 50 

VIJI. — CONSUMPTION  AND  THE  WAYS  IN  WHICH  IT  is  SPREAD 

BY  DUST 58 

IX. — DUST-DANGERS     OUT-OF-DOORS     AND    IN    PRIVATE 

HOUSES,  WITH  SUGGESTIONS  FOR  THEIR  AVOIDANCE  74 
X. — DUST-DANGERS   IN   PUBLIC   BUILDINGS  AND    PUBLIC 

CONVEYANCES 80 

XI.— SOME    OBJECTIONS,    PROTESTS,    AND    QUERIES    AN- 
SWERED       87 

XII. — SUMMARY  AND  CONCLUSION  .        .       .       .               .  101 

INDEX      .        .       *       * 107 


ILLUSTRATIONS. 


PAGE 

PLATE  I. — Different  forms  of  micro-organisms.      To  face     .         .     8 
FIG.  i — A. — A  single  "  colony  "  of  rod-shaped  bacteria  (bacilli) 
growing  on   a  plate  of  nutrient  gelatine.     The  actual 
diameter  of  this  colony  was  about  one  fourth  of  an  inch. 
B. — A  cluster  of  the  bacilli  taken  from   the  colony  and 
highly  magnified     ........     13 

FIG.  2. — The  "  plate  method  "  of  air  analysis    .         ,        .         .     17 
PLATE  II. — Colonies    of    micro-organisms    growing    on    dust 

particles.      To  precede      .         .         .         .         .         ,  "...     21 

PLATE  III.— Showing  results  of  "  plate  analyses"  of  the  air  of 

different  places  in  New  York.      To  face  .         .         .         .     24 

PLATE  IV. — Effect  of  sweeping  on  the  number  of  micro-organ- 
isms in  the  air.     To  face 32 

FIG.  3. — Ciliated  cells  from  the  large  air-tubes  of  the  human 

lungs,  seen  from  the  side 39 

FIG.  4. — Pigmentation  of  the  lung  from  inhaled  dust  .  .  44 
FIG.  5. — Dust  filters  in  the  lung — deeply  pigmented  .  .  .47 
FIG.  6. — Lymph  filters  (lymph-glands)  at  the  root  of  the  lung, 

the  seat  of  local  and  healed  tuberculosis  ....     69 


DUST  AND  ITS  DANGERS. 


CHAPTER  I. 

THE  NATURE  OF  DUST  IN  GENERAL. 

IF  this  were  not  a  practical  age,  and  if  the 
title  on  the  back  of  this  little  book  did  not 
fairly  promise  a  reasonably  practical  theme,  it 
might  be  thought  incumbent  on  the  writer, 
in  this  age  of  nice  analysis  of  very  small  things, 
to  be  explicit  at  the  outset  as  to  what  he  does 
or  does  not  mean  when  he  says  dust.  For  af- 
ter all,  when  we  think  of  it,  there  are  a  good 
many  kinds  of  dust.  There  is,  for  example, 
molecular  dust,  which  swaying  ever  in  space 
catches  and  breaks  the  sunbeams,  giving  us 
now  the  deep  blue  of  full  day  and  again  the 
gorgeous  colors  of  the  earlier  and  later  hours. 


DUST  AND  ITS  DANGERS. 


There  are  those  masses  of  "  water  dust "  which 
we  call  clouds  and  fogs  and  steam.  There  is 
the  scriptural  dust,  bearing,  according  to  ortho- 
dox traditions,  such  a  close  relationship  to  the 
origin  and  endings  of  mundane  existence.  Col- 
loquially, there  is  a  form  of  "dust"  too  which  to 
win  many  a  mortal  seems  to  forget  both  his 
origin  and  his  destiny,  yielding  at  last  that  dust 
which  he  has  won  to  be  himself  resolved  into 
that  to  which  he  was  foreordained. 

But  if  we  plant  our  standard  on  Webster's 
first  choice,  and  let  dust  be  for  us  "  Fine  dry 
particles  of  earth  or  other  matter  so  attenuated 
that  it  may  be  raised  and  wafted  by  the  wind," 
we  shall  not  be  apt  to  stray  too  far  from  the 
practical,  nor  fall  foul  of  either  primordial  or 
ecclesiastical  or  pecuniary  dust. 

Simple,  common,  omnipresent  every-day  dust 
then, — the  bane  of  the  tidy  housekeeper,  the 
torment  of  the  cleanly  citizen  who  goes  upon 
the  streets  in  ill-kept  towns,  wafted  upon  every 
breeze  without,  stirred  by  every  footfall  within, 
— this  is  the  humble  but  significant  subject  to 
which,  not  without  reason,  it  is  believed,  these 
pages  are  devoted. 


DUST  AND  ITS  DANGERS. 


The  dust  particles  of  the  air  may  be  roughly 
grouped  in  two  classes — first,  those  larger  bodies 
which  are  readily  visible  in-doors  or  out-doors, 
and  second,  the  smaller  particles  which  are  usu- 
ally only  seen  when  strongly  illuminated. 

The  coarser  particles  of  dust,  such  as  are 
usually  swept  into  our  faces  whenever  we  go 
upon  the  streets  in  New  York  in  dry  and 
windy  weather,  consist  largely  of  small  frag- 
ments of  sand,  broken  fibres  of  plants,  pollen, 
fine  hairs,  the  pulverized  excreta  of  various 
domestic  animals,  ashes,  fibres  of  clothing  and 
other  fabrics,  particles  of  lime  or  plaster  or 
soot,  parts  of  seeds  of  plants,  masses  and  clus- 
ters of  various  kinds  of  micro-organisms,  and 
other  partially  ground  up  materials  of  kinds 
too  numerous  to  mention. 

The  finer  dust  particles,  whose  presence, 
when  in  considerable  quantities,  we  may  be 
aware  of  by  the  choking  sensation  which  they 
cause  when  breathed  in,  even  though  we  do 
not  see  them,  are  most  plainly  visible  as  the 
so-called  "  motes  in  the  sunbeam,"  when  sunlight 
streams  into  more  or  less  darkened  places. 
These  are  very  light  and  consist  of  fragments 


DUST  AND  ITS  DANGERS. 


of  fine  vegetable  or  animal  fibres,  such  as  cot- 
ton or  woollen  or  other  light  material,  and  of 
the  greatest  variety  of  micro-organisms,  either 
singly  or  in  masses,  such  as  bacteria  and  mould 
spores.  Furthermore,  these  micro-organisms 
are  very  apt  to  be  found  clinging  singly  or 
in  clusters  to  the  larger  or  smaller  inorganic 
particles  of  one  kind  or  another  which  usually 
make  up  the  bulk  of  visible  or  invisible  dust  in 
inhabited  regions. 

It  is  not  necessary  for  our  purposes  here  to 
enter  in  detail  into  those  conditions  of  soil  and 
climate  and  human  occupation  which  favor  the 
presence  of  dust  in  the  air.  That  dry  air  and 
dry-ground  surfaces  and  winds  favor  the  distri- 
bution of  the  fine  particles  which  we  call  dust, 
and  that  still  air  and  moist  ground  tend  to  hold 
it  in  check,  are  facts  which  every  one's  observa- 
tion teaches. 

It  is  well  known  that  there  are  certain  occu- 
pations which  confine  persons  to  closed  rooms 
or  places  in  which  dust  particles  of  one  kind 
or  another  are  very  abundant.  Thus  day  after 
day  persons  confined  in  air  charged  with  coal- 
dust  or  stone-dust  or  metallic-dust  or  cotton- 


DUST  AND  ITS  DANGERS. 


or  woollen-dust  or  tobacco-dust,  etc.,  are  apt  to 
become  victims  of  more  or  less  well  marked 
pulmonary  affections,  which  are  to  be  found 
fully  described  in  systematic  treatises  among 
the  so-called  "  diseases  of  occupation." 

It  is  not  with  these  exceptional  places  nor 
with  the  special  conditions  which  belong  to 
them  that  we  are  now  concerned,  but  with  the 
conditions  under  which  both  well  and  sick  peo- 
ple of  all  classes  are  placed,  especially  in  cities, 
and  more  particularly  when  in-doors.  Nor 
shall  we  occupy  ourselves  here  to  any  consid- 
erable extent  with  the  inorganic  ingredients  of 
dust,  but  more  especially  with  those  living 
components  called  micro-organisms,  be  they 
either  bacteria  or  moulds. 

I  purpose,  in  the  first  place,  drawing  upon 
the  results  of  various  old  and  recent  studies,  to 
indicate  the  sources  of  the  living  germs  which 
form  such  an  important  part  of  the  dust  of  in- 
habited regions,  the  ways  in  which  they  get 
disseminated  in  the  air,  and  their  general  de- 
portment as  they  are  driven  hither  and  thither 
by  the  winds,  sway  poised  in  the  still  air  of  quiet 
places,  or  settle  slowly  to  the  ground. 


DUST  AND  ITS  DANGERS. 


I  purpose  then  to  show  the  difference  of 
conditions  which  prevail,  in-doors  and  out,  and 
the  significance  of  these  conditions  in  the 
problems  of  ventilation  and  cleanliness.  I 
shall  then  give  the  results  of  a  series  of  studies 
of  the  atmospheric  micro-organisms  in  various 
places,  and  consider  the  relationship  of  these 
aerial  germs  to  some  common  forms  of  disease. 
Finally,  I  shall  suggest  some  of  the  measures 
which  must  be  adopted,  both  by  the  public  au- 
thorities and  private  persons,  if  both  outof- 
doors  and  in-doors  we  are  to  have  the  privi- 
lege of  breathing  clean  and  wholesome  air.  I 
shall  not,  except  incidentally,  touch  upon  the 
ordinary  problems  of  ventilation  or  the  numer- 
ous ways  in  which  by  the  accumulation  of  the 
products  of  respiration  and  exhalation  the  air 
of  inhabited  rooms  may  become  an  active 
source  of  discomfort  and  ill-health,  because  the 
means  by  which  these  evils  may  be  avoided  are 
well  known  and  are  fully  explained  under  the 
heading  of  ventilation  in  text-books  and  treatises 
on  hygiene. 


CHAPTER   II. 

THE    LIVING    ELEMENTS    OF    DUST  ;     WHAT    THEY 
ARE    AND    WHERE    THEY    COME    FROM. 

ALL  those  forms  of  minute  vegetable  life 
which  swarm  in  myriads  almost  every- 
where upon  the  earth's  surface  are  called  in 
general  micro-organisms  or  germs.  Among 
these  there  are  three  prominent  forms  which 
are  called  bacteria,  yeasts,  and  moulds  (see 
Plate  I.).  Among  these  the  bacteria  are  by 
far  the  most  important.  These  tiny  organisms 
are  for  the  most  part  so  very  small  that  many 
thousands  or  millions  of  them  clustered  closely 
together  would  not  make  a  mass  larger  than 
the  head  of  a  pin.  Some  of  them  are  round 
or  ovoidal,  some  rod-like,  some  spiral  (see 
Plate  I.  Fig.  3).  Most  of  them  are  harmless 
to  man,  and  serve  a  very  important  purpose 
in  the  economy  of  nature  in  tearing  asunder 

7 


8  DUST  AND  ITS  DANGERS. 

dead  and  worn-out  organic  material  and  setting 
it  free  in  suitable  condition  for  the  building  up 
of  new  forms  of  life.  A  few  species  of  bacteria, 
however,  are  capable  of  causing  some  of  the 
most  wide-spread  and  most  dreaded  of  human 
diseases. 

The  writer  has  in  another  book '  described 
in  simple  and  untechnical  manner  the  various 
forms  of  bacteria  and  their  relationship  to  man, 
and  to  this  he  must  refer  the  reader  for  fur- 
ther details  as  to  their  nature  and  life  history. 

The  moist  surfaces  of  decaying  vegetables 
and  plants  and  the  bodies  of  animals,  all  solid 
excreta  of  the  bodies  of  men  and  animals, 
human  sputum,  stagnant  water,  the  surface  of 
the  soil  in  inhabited  regions,  etc.,  afford  fertile 
fields  of  growth  for  myriads  of  micro-organisms 
of  one  kind  or  another. 

But  we  should  always  remember  that  bacte- 
ria do  not  become  detached  from  the  surfaces 
or  materials  on  which  they  grow  or  are  lodged 
while  these  are  in  the  moist  condition.  Even 
the  air  sweeping  in  strong  currents  through 
sewers  whose  watery  contents  and  moist  walls 

1  "  The  Story  of  the  Bacteria." 


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DUST  AND  ITS  DANGERS. 


may  be  swarming  with  bacteria  does  not  be- 
come charged  with  these.  The  bacteria,  singly 
or  in  masses,  free,  or  attached  to  other  par- 
ticles of  one  kind  or  another,  must  first  be 
dried  and  then  the  clusters  more  or  less  pul- 
verized or  ground  up,  before  they  are  swept 
away  and  suspended  as  a  part  of  the  dust  in 
the  air. 

There  are  indeed  certain  moulds — the  green 
mould,  for  example,  which  is  so  common  on 
various  moist  articles  of  food — which  form 
very  light  and  not  easily  moistened  spores  (see 
Plate  I.  Fig.  i),  these  may  be  readily  brushed 
or  blown  off  and  mingle  with  the  dust  under 
almost  all  conditions. 

All  sorts  of  bacteria-laden  material  then, 
when  dry  and  ground  up  as  it  so  readily  is 
by  the  varied  movements  of  men  and  animals 
put-doors  and  in-doors,  may  become  a  part 
of  the  floating  dust.  These  dry  minute  germs, 
some  of  which  are  alive  and  some  dead,  com- 
port themselves  in  the  air  just  as  lifeless  dust 
particles  of  any  other  kind  do.  They  are 
wholly  inert,  and  are  driven  hither  and  thither 
by  air  currents,  now  in  clouds  or  masses  of  al- 


10  DUST  AND  ITS  DANGERS. 

most  stifling  density,  and  again  in  very  small 
numbers,  collecting  in  whirls  and  eddies,  and 
finally,  always  sooner  or  later,  settling  down  to 
the  lowest  available  resting-place,  as  soon  as 
the  buoyancy  of  air  currents  gives  way  to  the 
ever  acting  attraction  of  gravitation.  Since 
the  bacteria  of  dust  are  very  apt  to  be  in  little 
groups  or  clusters  or  to  cling  to  other  dust  par- 
ticles, most  of  them  readily  settle,  so  that  a 
very  considerable  part,  in  fact,  of  the  finer 
dust — the  "  motes  in  the  sunbeam  " — is  not 
made  up  of  bacteria  or  germs  but  of  other 
forms  of  lifeless  matter. 


CHAPTER  III. 

HOW      THE     LIVING      ELEMENTS     OF      DUST      ARE 
STUDIED. 

HOW  do  we  find  out  how  many  living 
germs  there  are  and  of  what  kinds  in 
a  given  volume  of  air  ?  It  will  suffice  for  our 
purposes  here  to  say  that  the  bacteria  are  so 
extremely  small  that  the  search  for  them  as 
they  occur  in  nature  is  ordinarily  of  little  avail 
by  the  simple  use  of  the  microscope. 

We  have  recourse  in  such  studies  to  what  is 
called  the  "  culture  method."  x  By  this  method, 
instead  of  bringing  a  portion  of  fluid  or  of  the 
air  in  which  we  wish  to  seek  for  bacteria  di- 
rectly under  the  microscope,  we  mix  a  small 
portion  of  the  fluid  or  air  with  some  material 
which  serves  as  food  for  the  germs,  and  on  or 
in  which  they  will  readily  grow. 

1  See  "  The  Story  of  the  Bacteria." 
II 


12  DUST  AND  ITS  DANGERS. 

This  food  medium  usually  contains  some 
form  of  gelatine.  The  gelatinized  material  is 
usually  melted  when  the  planting  is  being  done, 
and  when  it  cools  the  bacteria  are  held  firmly 
in  the  position  in  which  they  lodged  when  they 
were  put  in. 

The  bacteria  placed  under  these  conditions 
multiply  with  such  great  rapidity  that  usually 
in  a  short  time  the  progeny  of  a  single  living 
germ  will  have  accumulated  to  such  a  degree 
right  in  the  spot  where  the  germ  lodged 
that  the  mass  of  them,  which  we  call  a  "  col- 
ony "  will  be  readily  visible  to  the  naked  eye, 
or  under  a  low  power  of  the  microscope  (see 
Fig.  i).  Now  since  we  can  readily  see  the 
mass  of  bacteria  which  has  grown  where  only 
a  single  germ  had  lodged  we  have  only  to 
count  the  colonies  to  know  how  many  living 
bacteria  were  present  in  the  volume  of  air 
or  fluid  which  we  have  tested. 

We  can  now,  futhermore,  subject  the  little 
colonies  which  form  our  bacterial  crop  to  a  va- 
riety of  examinations  and  tests,  and  make  out 
what  kinds  there  are,  and  further  learn  their 
effects  upon  man  or  animals. 


DUST  AND  ITS  DANGERS. 


Now  a  good  many  plans  have  been  devised 

for  finding    out  how  many  living  germs  are 

present  in  a  given  volume  of  dusty  air.     We 

A 


FIG.    I. 


Fig.  i.  A — A  single  "colony"  of  rod-shaped  bacteria  (Bacilli) 
growing  on  a  plate  of  nutrient  gelatine.  The  actual  diameter  of  this 
colony  was  about  one-fourth  of  an  inch.  B — A  cluster  of  the  bacilli 
taken  from  the  colony  and  highly  magnified. 

may  force  a  given  volume  of  the  air  through  a 
tube  which  has  been  plugged  with  cotton-bat- 
ting previously  heated  so  hot  as  to  kill  any 


14  DUST  AND  ITS  DANGERS. 

germs  which  by  chance  have  been  upon  it. 
The  cotton  if  properly  packed  in  the  tube  will 
catch  and  hold  entangled  in  its  meshes  all  the 
dust  particles  no  matter  how  small,  and  with 
these  all  the  bacteria  which  were  in  the  air 
which  we  force  through  the  tube.  If  now  we 
carefully  pull  out  the  cotton  plug  with  a  pair 
of  perfectly  clean  forceps,  and  thoroughly  rinse 
it  off  in  a  small  clean  flat  dish  containing  our 
bacterial  food — which  we  call  "  the  culture  me- 
dium,"— the  germs  will  be  distributed  through 
the  medium,  and  we  cover  the  dish  and  set  it 
aside  in  a  warm  place  and  let  it  stand  until 
each  living  germ  has  grown  and  multiplied  till 
it  forms  a  visible  colony.  Now  we  count  the  col- 
onies, and  the  number  represents  the  number  of 
living  germs  which  were  present  in  the  whole 
volume  of  air  which  we  forced  through  the  cot- 
ton plug.  There  are  of  course  many  details 
and  precautions  against  error  which  must  be 
observed,  but  this  brief  description  will  suffice 
for  our  purposes  here. 

It  has  been  found  in  practice,  however,  that 
it  is  better  to  use  fine  sand  than  cotton  in  the 
tubes  to  catch  the  germs,  since  this  is  more 


DUST  AND  ITS  DANGERS.  15 

easily  handled  and  is  equally  efficient  as  a 
filter.  We  plant  the  sand  together  with  the 
dust  which  it  has  caught  in  the  melted  culture- 
medium,  allow  it  to  cool  and  then  stand  for  a 
few  days,  and  when  the  colonies  are  grown  they 
are  easily  distinguished  from  the  sand  particles 
by  their  shape,  color,  etc.,  and  can  be  readily 
counted.  Or,  we  may  use  granulated  sugar 
for  a  filter,  which  finally  dissolves  in  the  culture- 
medium,  leaving  the  bacteria  to  grow  in  due 
time.  This  may  be  called  the  "  filtration 
method  "  of  air  analysis. 

As  it  requires  an  accurate  and  somewhat 
complex  and  cumbersome  apparatus  to  force 
or  draw  the  air  through  either  the  cotton  or 
sand  filter,  another  and  simpler  method  is 
often  resorted  to,  which,  though  in  some  re- 
spects less  accurate,  still  gives  very  useful 
results  when  we  wish  simply  to  compare  the 
germ  ingredients  of  the  air  in  one  place  with 
those  in  another  under  similar  general  condi- 
tions. 

This  simpler  method  consists  in  pouring  into 
a  series  of  perfectly  clean  shallow  glass  dishes 
a  thin  layer  of  the  warm  gelatinous  culture- 


1 6  DUST  AND  ITS  DANGERS. 

medium  and  allowing  it  to  solidify  by  cooling. 
This  gives  a  smooth,  moist,  somewhat  adhesive 
surface  of  equal  size  in  each  of  the  dishes, 
which  are  immediately  protected  from  any 
chance  contamination  by  closely-fitting  glass 
covers. 

This  mode  of  air  analysis  depends  upon  the 
fact  which  we  have  mentioned  above,  and 
which  everybody  is  familiar  with,  namely,  that 
all  dust  particles,  light  or  heavy,  in  quiet  places, 
slowly  but  surely  settle  towards  the  ground. 
If  now  we  set  one  of  our  covered  dishes  in  a 
still  place  and  take  off  the  cover,  the  dust 
particles,  the  inorganic  as  well  as  the  living, 
will  settle  on  to  this  moist  nutrient  surface. 
With  the  inorganic  components  of  the  dust,  the 
multifarious  shreds  and  patches  of  one  thing 
or  another,  this  is  the  end  of  the  matter.  But 
as  the  living  dust  particles  touch  the  surface, 
like  Antaeus,  they  find  their  abeyant  vigor 
quickly  renewed,  and  forthwith  commence  to 
multiply  and  inherit  their  little  new-found 
earth.  Now,  suppose  we  leave  our  dishes  un- 
covered and  exposed  to  the  falling  dust  for, 
say  five  minutes  ;  suppose  further  that  the  sur- 


DUST  AND  ITS  DANGERS.  I/ 

face  of  the  culture-medium  is  three  square 
inches  in  size,  it  will  be  readily  seen  that  by 
the  exposure  of  dishes  of  the  same  size  for  the 


FIG.  2. — THE  "PLATE  METHOD"  OF  AIR  ANALYSIS. 
The  cut  shows  the  appearance  of  the  flat,  shallow  dish,  the  bottom 
of  which  was  covered  with  nutrient  gelatin,  and  when  this  had  cooled 
and  solidified,  was  uncovered  and  exposed  to  the  air  in  a  moderately 
clean  place  for  five  minutes.  It  was  then  allowed  to  stand  in  a  warm 
place  for  four  days.  Immediately  after  the  exposure  of  the  gelatin 
to  the  air  nothing  whatsoever  was  visible  on  its  surface.  But  within 
a  few  hours  tiny  spots  appeared  which  grew  larger,  some  more  rapidly 
than  others.  These  ' '  colonies, "  at  the  end  of  four  days,  when  the  draw- 
ing was  made,  vary  considerably  in  size  and  appearance,  because  they 
are  mostly  made  up  of  different  species  of  germs.  Each  colony  con- 
sists of  thousands  of  germs  (see  Fig.  I,  A),  which  have  grown  on  the 
spot  where  the  lone  ancestor  fell  from  the  air  and  stuck  fast  during 
the  five  minutes  exposure  of  the  gelatin. 

same  time  to  the  air  of  different  places,   we 
can,   by  comparing   the   number   of   bacterial 


DUST  AND  ITS  DANGERS. 


colonies  which  develop  on  the  surfaces,  get  at 
least  an  approximate  idea  of  the  relative  num- 
ber of  suspended  bacteria  slowly  settling  in  the 
air  of  the  different  places  (see  Fig.  2). 

We  cannot,  of  course,  by  this  method  say 
how  many  germs  were  present  in  a  given  vol- 
ume of  air,  as  we  can  by  the  more  elaborate 
and  accurate  method  given  above,  and  there 
are  many  minor  sources  of  error.  For  exam- 
ple, the  mould  spores  are  so  very  light  and 
buoyant  that  they  fall  but  slowly,  so  that  we 
may  altogether  miss  many  of  them,  and  the 
same  may  be  true  of  some  of  the  lighter  bac- 
teria. Moreover,  even  very  slight  upward  air 
currents  may  interfere  with  the  settling  of  the 
germs,  and  in  windy  places  this  method  is  of 
little  use.  But  on  the  whole,  if  similar  condi- 
tions are  maintained  in  the  different  analyses, 
comparative  results  may  be  obtained  in  this 
way  which  are  of  much  value,  as  we  shall  pres- 
ently see. 

This,  which  we  will  call  the  "plate-method," 
enables  us  to  get  a  general  notion  of  the  bac- 
terial contents  of  the  air  in  various  places  under 
conditions  which  would  render  the  use  of  the 


DUST  AND  ITS  DANGERS. 


more  accurate  and  cumbersome  apparatus  dif- 
ficult or  impracticable.  We  can  go  about  with 
our  innocent-looking  little  case  of  glass  boxes, 
partly  filled  with  nutrient  gelatin,  as  does  the 
amateur  photographer  with  his  detective  cam- 
era ;  though  instead  of  "  pulling  the  string, 
touching  the  button,  and  leaving  the  rest  to 
the  manufacturer,"  we  raise  the  cover,  take  the 
time,  and  let  Nature  do  the  rest. 

We  are  now  ready  to  look  at  the  results  of 
a  series  of  so-called  biological  analyses  of  the 
air  of  various  places.  We  mean  by  biological 
analysis  of  air,  in  distinction  from  the  chemical, 
an  analysis  which  has  for  its  object  the  deter- 
mination of  the  number  or  character,  or  both, 
of  the  living  germs,  or  micro-organisms  which 
may  be  suspended  in  it. 


CHAPTER  IV. 

THE     MICRO-ORGANISMS    OF    OUT-OF-DOORS    DUST. 

WE  must  be  on  our  guard  in  looking  at 
the  results  of  such  analyses  as  those 
now  to  be  described  against  hasty  inferences 
as  to  their  significance.  It  would  be  a  grave 
mistake  to  suppose  that  living  germs  in  the 
air  are  necessarily  harmful  to  human  beings, 
and  to  infer  that  air  found  to  habitually  con- 
tain few  bacteria  is  necessarily  more  salubrious 
than  that  which  contains  more.  For  the  pres- 
ent, then,  let  us  look  upon  the  results  of  these 
analyses  simply  from  the  biological  standpoint, 
and,  if  possible,  place  ourselves  in  the  attitude 
of  botanists  studying  the  flora  of  the  atmos- 
phere, not  of  physiologists  concerned  with  the 
relationship  of  these  tiny  plants  to  man.  This 
we  shall  come  to  by  and  by  when  we  have  ac- 
cumulated enough  facts  to  justify  such  infer- 
ences as  may  urge  themselves  upon  us. 

20 


EXPLANATION  OF  PLATE  II. 


This  cut  shows  the  appearances  which  are  presented,  after  the 
germs  have  grown,  by  particles  of  sand  and  shreds  of  vegetable  fibre 
to  which  single  germs  were  clinging  when  they  settled  on  to  the  un- 
covered gelatin  plate.  In  this  case  the  drawing  was  made  five  days 
after  the  exposure  of  the  plate  to  the  air  of  a  dusty  street.  The  largest 
of  these  colonies  were  barely  visible  to  the  naked  eye. 

i. — Shows  a  particle  of  sand  completely  surrounded  by  the  colony 
or  mass  of  bacteria  which  has  grown  from  a  single  germ  which  was 
clinging  to  the  minute  sand  particle  as  it  settled  with  the  dust. 

2. — Shows  a  tiny  shred  of  wood  to  which  five  different  germs  were 
attached  as  it  settled  on  to  the  exposed  plate.  We  should  probably 
have  searched  in  vain,  even  with  a  powerful  microscope,  for  the  single 
germs  clinging  to  it  at  the  time  this  wooden  dust  particle  planted  itself 
on  the  surface  of  the  gelatin.  But  now  the  larger  colonies  are  visible 
even  to  the  naked  eye.  We  know  that  they  grew  from  different 
species  of  germs  because  under  a  moderate  magnifying  power  they 
present  such  markedly  different  appearances. 

3. — Shows  a  minute  sliver  to  which  four  different  forms  of  germs 
were  clinging  as  it  fell. 


DUST  AND  ITS  DANGERS.  21 

From  the  enormous  number  of  bacteria  and 
moulds,  which  are  present  everywhere  in  in- 
habited regions  where  the  conditions  are  suit- 
able for  their  growth,  it  might  be  imagined 
that  in  dry  weather  the  number  of  atmospheric 
germs  in  the  dust  out-of-doors  would  be  very 
great.  But  this  is  not  usually  the  case,  even 
in  large  and  populous  towns. 

Here  and  there  along  the  streets,  where 
these  are  filthy  and  almost  never  properly 
cleaned,  or  where  the  wind  whirls  around  the 
corners  of  buildings,  forming  air  eddies,  the 
micro-organisms  are  often  present  in  very  large 
numbers,  so  that  one  in  passing  about  the  town 
is  apt  here  and  there  to  encounter  veritable 
germ-showers.  But  on  the  whole,  almost 
everywhere  out-of-doors,  except  in  dangerously 
filthy  cities,  the  large  volumes  of  air,  which  are 
more  or  less  constantly  passing,  so  largely  di- 
lute the  local  germ-dusty  air  that  the  actual 
number  of  micro-organisms  in  a  given  volume, 
say  a  cubic  foot,  is  on  the  average  very  small, 
and  usually  insignificant.  When  the  ground 
is  wet  and  air  currents  moderate,  the  number 
of  germs  is  still  further  diminished. 


22  DUST  AND  ITS  DANGERS. 

It  is  very  difficult  to  fix  upon  any  definite 
number  of  living  micro-organisms  in  the  out- 
of-doors  air  which  can  be  regarded  as  the  usual 
or  normal  number,  because  the  number  varies 
so  extremely  under  different  conditions.  Thus 
on  high  mountains  or  deserts  and  on  the  sea 
the  unconfined  air  is  practically  free  from 
micro-organisms.  In  the  winter  months,  when 
snow  is  on  the  ground,  during  rain  storms,  and 
when  the  air  is  still,  the  number  may  be  very 
small.  On  the  other  hand,  a  high  wind  blowing 
across  a  region  rich  in  dry  and  pulverized 
germ-laden  material,  will  for  a  time  disseminate 
large  numbers  of  micro-organisms  ;  but  at  the 
same  time  it  tends,  by  the  dilution  which  it 
affords,  and  by  carrying  them  off  to  other  re- 
gions, to  speedily  reduce  the  numbers  in  any 
given  place.  A  rainfall,  to  a  certain  extent, 
tends  to  free  the  air  of  its  germs  by  washing 
them  down,  while  during  a  snowstorm  many 
are  caught  in  the  snow  crystals  as  they  form. 

In  wet  weather  mould-spores  tend  to  pre- 
dominate, partly  because  they  then  grow  readily 
and  partly  because  they  are  very  light,  and  not  as 
easily  wetted  and  held  down  as  are  the  bacteria. 


DUST  AND  ITS  DANGERS.  2$ 

The  analysis  of  out-of-doors  air  shows,  as 
might  be  expected,  a  great  deal  of  variation 
in  the  number  of  living  germs  present  in  a 
given  volume.  Ten  litres,  which  is  about  600 
cubic  inches  (that  is  a  volume  equal  to  a  cube 
of  about  8  inches  square),  is  the  volume  of 
air  usually  taken  as  a  sample  for  purposes  of 
analysis. 

Carnelly  found  in  still  out-of-doors  air,  in 
the  town  of  Dundee,  in  Scotland,  as  the  result 
of  14  analyses,  an  average  of  less  than  10 
bacteria  in  10  litres  of  air,  while  in  another 
place  there  were  over  1 70  in  the  same  volume. 

Tucker  found  the  air  in  Boston,  from  a 
secluded  place,  but  in  the  immediate  vicinity 
of  its  traffic,  during  the  mild  but  rather  windy 
weather  in  November,  December,  and  January, 
with  no  snow  on  the  ground,  to  contain  on  the 
average  of  56  analyses,  less  than  20  bacteria  to 
10  litres.  In  an  open  court  at  the  Hygienic 
Institute  in  Berlin,  Petri  found,  as  a  rule, 
equally  small  numbers. 

The  average  of  1 3  analyses,  made  in  March 
and  April,  1 890,  of  the  air  from  the  yard  of  the 
College  of  Physicians  and  Surgeons,  in  New 


24  DUST  AND  ITS  DANGERS. 

York,  at  a  place  as  far  from  the  streets  as  pos- 
sible, and  about  25  feet  from  the  ground,  showed 
the  number  of  bacteria  in  10  litres  to  be  56  and 
of  moulds  4. 

Analyses,  during  the  same  period,  of  the  air 
of  the  streets  in  New  York,  from  various  parts 
of  the  town,1  showed  the  average  number  of 
bacteria  in  10  litres  to  be  376,  and  of  moulds 
6.  These  analyses  of  street  air  were  made 
under  ordinary  conditions,  at  such  times  of  the 
day  as  the  air  appeared  to  be  at  its  best. 

If  an  analysis  is  made  of  the  air  in  the  dust 
clouds  which  sweep  along  the  ill-kept  streets 
of  a  city  like  New  York  or  which  blows  from 
the  street  sweepers  as  they  pass  along  the 
unwatered  thoroughfares  into  the  houses  or 
over  the  unwary  passer-by,  the  numbers  of 
germs  to  the  litre  is  startling. 

Let  us  look  at  a  graphic  record  of  the  rela- 
tive number  of  bacteria  in  various  places,  made 
by  the  plate  method  already  described. 

Plate  III.  shows  the  result  of  a  series  of 
comparative  analyses  made  in  this  way  in  var- 

1  This  was  at  a  time  when  the  so-called  politicians  were  juggling 
with  the  Street  Cleaning  Department  while  the  streets  were  largely 
left  to  take  care  of  themselves. 


PLATE  III.— SHOWING   RESULTS    OF  "  PLATE  ANALYSES  "  OF   THE   AIR 
OF   DIFFERENT   PLACES   IN   NEW   YORK. 

(See  explanation  in  the  text.) 


DUST  AND  ITS  DANGERS.  2$ 

ious  places  in  New  York  on  a  clear,  dry,  mod- 
erately breezy  day,  in  April,  1890.  Each  one 
of  the  spots  represents  a  colony  of  bacteria, 
which  has  grown  from  the  single  germ  which 
settled  on  to  the  moist  surface  during  the  five 
minutes  exposure  to  the  air. 

1.  Ball  Ground,   Central  Park. — A  mod- 
erate westerly  wind  bringing  dust  over  from 
the  Eighth  Avenue  and  its  cross  streets. 

2.  Union    Square. — At   the   edge    of    the 
fountain  basin. 

3.  The  library  of  a  private  house  not  far 
from  34th  Street  and  Broadway. 

4.  A  large  retail  dry-goods  store  on  one  of 
the  uptown  cross  streets  near  Broadway,  during 
a  busy  hour  of  the  day,  when  there  was  much 
stir  and  bustle. 

5.  Railing  of  the  small  park  at  Broadway 
and  35th  Street. 

6.  A  cross  street  through  which  the  carts  of 
the  Street-Cleaning  Department  were  passing 
collecting  the  dry  heaps  of  street  dirt. 

If  we  translate  into  numbers  the  appearances 
of  the  cultures  shown  in  Plate  III.,  we  find  that 
during  five  minutes  the  number  of  living  germs 


26  DUST  AND  ITS  DANGERS. 

which  settled  from  the  floating  dust  on  to  the 
bottom  of  a  round  dish  about  3f  inches  in 
diameter  in  different  places  in  New  York  was 
as  follows : 

1.  Central    Park. — Dust   blowing  from  an 
adjacent  street,  499. 

2.  Union  Square,  214. 

3.  Private  house,  34. 

4.  Large  retail  dry  goods  store,  199. 

5.  Broadway  and  35th  Street,  941. 

6.  Street  in  the  process  of  being  cleaned,  by 
the  Street-Cleaning  Department,  5,810. 

A  sufficient  explanation  of  the  number  of 
germs  in  the  air  at  the  lower  part  of  Central 
Park  is  found  in  the  westerly  wind  and  the  ex- 
tremely filthy  condition  of  the  streets  on  the 
windward  side.  The  result  of  the  analysis 
shown  in  fig.  6,  needs  no  lengthy  comment. 
That  as  many  living  germs  as  of  colonies 
which  are  here  seen  growing  should  be  float- 
ing in  the  air  and  liable  to  be  breathed  in  by 
any  unfortunate  passer-by  within  five  minutes, 
is  evidence  enough  of  the  filthiness  of  the 
practices  of  so-called  street-cleaning.  As  to 
its  danger,  more  by  and  by. 


CHAPTER  V. 

THE    MICRO-ORGANISMS    OF    IN-DOORS    DUST. 

WHEN  we  consider  the  comportment  of 
dust  particles  in  closed  rooms,  we  see 
at  once  that  the  great  renovating  and  cleansing 
agency  which  is  so  efficient  out-of-doors  is,  ex- 
cept on  special  occasions,  absent,  namely,  the 
winds  and  strong  air  currents  and  the  more  or 
less  frequent  and  prolonged  wettings.  Once 
in  a  closed  room  dust  is  very  apt,  as  every 
housekeeper  knows,  to  stay  there,  unless 
special  means  are  resorted  to  to  get  rid  of  it. 
But  although  the  dust  remains  in  the  room, 
those  heavier  parts  of  it  which  contain  most  of 
the  bacteria  gradually  sink  to  the  lowest 
available  levels,  floors,  shelves,  furniture,  etc., 
so  that  it  has  been  found  that  the  still  air  of  a 
room  may  almost  completely  free  itself  from 
micro-organisms,  except  some  of  the  lighter 

27 


28  DUST  AND  ITS  DANGERS. 

mould  spores,  within  one  or  two  hours.  Of 
course  violent  currents  of  air,  walking  about, 
etc.,  interfere  with  the  very  complete  subsi- 
dence of  the  bacteria-laden  dust  particles. 

Now  it  might  be  supposed  that  the  frequent 
renewal  of  the  air  of  a  room  by  such  a  system 
of  ventilation  as  would  be  effective  in  keeping 
its  gaseous  ingredients  pure  would  also  suffice 
to  rapidly  carry  off  dust  particles,  and  bacteria 
as  well.  But  a  long  series  of  most  carefully 
conducted  experiments  by  Stein  has  shown 
that  this  is  not  the  case.  Even  when  the  in- 
troduction of  fresh  air  is  pushed  to  the  com- 
plete renewal  of  the  air  three  times  an  hour, 
the  number  of  suspended  micro-organisms 
floating  in  the  air  is  scarcely  more  diminished 
than  they  would  be  by  settling  in  still  air. 
Stein  found  that  only  when  the  ventilation 
was  carried  to  the  degree  of  inducing  marked 
and  disagreeable  draughts  in  the  room  was 
there  a  rapid  diminution  in  the  number  of 
micro-organisms  which  had  been  diffused  arti- 
ficially through  the  air  for  the  purposes  of  the 
test.  Of  course  opening  of  the  windows  and 
allowing  large  bodies  of  air  to  blow  through 


DUST  AND  ITS  DANGERS. 


the  room,  quickly  resulted  in  sweeping  away  a 
large  proportion  of  the  suspended  micro-or- 
ganisms. But  this  observer  also  found  that 
even  very  strong  air  currents  were  not  able, 
when  sweeping  over  woollen  and  other  fabrics, 
carpets,  hangings,  etc.,  which  had  been  be- 
strewn with  bacteria-laden  dust,  to  free  the 
germs  to  any  considerable  extent  from  these. 
The  strong  air  currents  carried  off  the  sus- 
pended particles,  but  those  which  had  settled 
on  to  the  fabrics  and  floors  were  but  little 
affected.  The  practical  bearings  of  this  ob- 
servation we  shall  see  by  and  by. 

When  we  consider  the  constant  tendency  of 
dust  particles  to  settle  as  soon  as  they  find 
themselves  in  quiet  places  out  of  strong  air 
currents,  and  the  fact  that  even  ordinarily 
efficient  systems  of  ventilation  do  not  carry  off 
any  considerable  proportion  of  the  dust  par- 
ticles from  closed  still  rooms,  we  are  led  to  the 
rather  startling  conclusion  that  the  ordinary 
living-rooms,  even  though  they  be  well  ven- 
tilated, are  actually  dust  and  bacteria  reposi- 
tories, and  that  when  by  a  system  of  forced 
ventilation  we  cause  large  volumes  of  dust- 


3O  DUST  AND  ITS  DANGERS. 

laden  air  from  out-of-doors  to  pass  through 
them  we  are  actually,  so  far  as  micro-organisms 
are  concerned,  cleansing  the  air  and  sending  it 
out  much  freer  from  germs  than  when  it  en- 
tered, these  having  slowly  settled  as  the  air 
made  its  way  from  the  entrance  to  the  exit  of 
the  ventilating  openings.  The  same  of  course 
applies,  though  in  a  less  striking  way,  to  the 
so-called  natural  mode  of  ventilation — that  is 
a  ventilation  system  which  has  for  its  exit  a 
warm  air-shaft  or  chimney,  and  "  trusts  to 
luck "  for  channels  of  air  entrance  through 
loose  joints  in  windows,  doors,  and  walls. 

Now,  although  in  rooms  through  which  for 
purposes  of  ventilation  large  volumes  of  dusty 
out-of-doors  air  are  pumped,  day  and  night, 
there  will  be  in  the  aggregate  a  considerable 
accumulation  of  more  or  less  bacteria-laden 
dust,  it  is,  after  all,  the  ground-up  dirt  which 
we  bring  in  from  the  streets  upon  our  shoes 
and  garments,  and  the  accumulations  of  waste 
material,  which  in  dwelling-houses  and  places 
of  assembly  are  so  abundant,  which  furnish  the 
larger  proportion  of  the  bacterial  ingredients 
of  in-doors  air.  The  marked  difference  be- 
3 


DUST  AND  ITS  DANGERS. 


tween  the  atmospheric  dust  in  closed  rooms 
and  that  out-of-doors  is  that  in  the  former 
there  is  no  spontaneous  mode  of  purification 
of  the  air  except  that  of  settling,  and  that  the 
settled  more  or  less  bacteria-laden  dust  is 
liable  to  frequent  stirring-up  by  the  ordinary 
movements  of  people,  while  out-of-doors  the 
bacteria-laden  air  is  constantly  being  swept  off 
by  the  wind. 

The  effect  of  stirring  about  in  rooms  in 
which  micro-organisms  are  present  is  shown  by 
the  analyses  of  Tucker  in  the  wards  of  the 
Boston  City  Hospital.  He  found  that  about 
midnight  after  the  wards  had  been  quiet  for  a  few 
hours,  the  number  of  living  bacteria  in  10  litres 
of  air  ranged  from  o  to  13,  while  the  number  of 
mould  spores  ranged  from  o  to  4.  The  air  had 
practically  freed  itself  from  germs,  by  settling 
to  floors  and  beds.  He  found  that  in  a  long 
series  of  hourly  determinations  in  various  wards 
at  all  hours  of  the  day,  the  average  number  of 
bacteria  in  10  litres  of  air  was  about  26  and  of 
moulds  about  12,  the  number  of  bacteria  rang- 
ing from  i  to  477;  of  moulds  from  o  to  227. 
The  germs  were  more  abundant  in  the  air  in 


32  DUST  AND  ITS  DANGERS. 

the  forenoon  when  the  beds  were  being  made 
and  the  wards  cleaned  and  put  in  order.  He 
found  that  sweeping  nearly  doubled  the  number 
of  germs  in  the  air  already  disturbed  by  the 
routine  work  in  the  wards  in  the  morning,  and 
considering  the  number  of  germs  in  the  10 
litres  of  air  in  the  early  morning  before  the 
wards  were  astir  as  the  minimum — i — the 
general  cleaning  routine  work  and  sweepkig 
were  capable  of  increasing  the  number,  on  the 
average,  seventy  times. 

The  difference  in  the  number  of  living  germs 
floating  in  the  air  of  a  room  before  and  after 
sweeping,  is  graphically  shown  in  Plate  IV. 
The  room  in  which  these  analyses  were  made, 
was  a  most  carefully  kept  hospital  ward  in  New 
York,  in  which  were  about  25  persons.  Be- 
fore the  sweeping,  when  quiet  had  prevailed 
for  about  an  hour,  the  number  of  living  germs 
which  settled  on  to  the  dish,  3^  inches  in  di- 
ameter, was  12  (see  Plate  IV.,  Fig.  i).  Im- 
mediately after  sweeping,  the  number  which 
settled  on  to  a  similar  surface,  was  226  (see 
Plate  IV.,  Fig.  2).  Very  much  larger  differ- 
ences are  often  found  in  the  number  of  germs 


DUST  AND  ITS  DANGERS.  33 

in  the  air  before  and  after  sweeping,  if  the 
rooms  are  not  frequently  carefully  and  properly 
swept  and  dusted.  Thus  in  a  carpeted  living- 
room  in  a  tenement  on  loth  Avenue,  75  bacteria 
and  i  mould  settled  on  to  the  surface  of  the 
exposed  plate  in  five  minutes  before  sweeping. 
When  the  room  was  still,  immediately  after 
sweeping,  a  similar  experiment  showed  over 
2,700  bacteria  and  6  moulds. 

Carnelly  found  in  hospital  wards  in  Dundee 
in  the  afternoons  from  10  to  20  bacteria  in  10 
litres  of  air.  Neumann  found  after  sweeping 
from  80  to  140  bacteria,  and  later  in  the  day 
from  4  to  10  in  10  litres.  On  the  other  hand, 
Carnelly  found  in  houses  which  are  denomin- 
ated clean,  180  bacteria  in  10  litres  of  air. 
while  in  very  dirty  houses  there  were  over 
900.  In  dirty  school-rooms,  with  the  so-called 
natural  ventilation,  he  found  in  the  same  vol- 
ume of  air  nearly,  2,000  living  bacteria,  while 
in  mechanically  ventilated  schools  there  were 
from  30  to  300. 

The  writer  has  found  as  the  result  of  23 
analyses  of  the  air  of  various  laboratories, 
lecture-rooms,  and  hall-ways,  at  the  College  of 


34  DUST  AND  ITS  DANGERS. 

Physicians  and  Surgeons  in  New  York,  under 
the  ordinary  conditions  of  occupation  by  con- 
siderable numbers  of  students  during1  March  and 
April,  1890,  that  the  average  number  of  bacteria 
in  10  litres  was  n  and  of  moulds  14. 

The  average  number  of  germs  in  various 
hospitals  and  dispensaries  in  New  York  during 
the  same  period  in  10  litres  of  air,  (19  analyses) 
was  bacteria  127,  moulds  25. 

We  thus  see  that  the  number  of  living  germs 
in  a  given  volume  of  in-doors  air  varies  greatly 
in  different  places  and  under  different  con- 
ditions. We  see  that  the  temporary  freeing  of 
the  in-doors  air  from  germs  can  be  accomplished 
by  simply  closing  the  rooms  and  keeping  the 
contained  air  still  when  within  one  or  two 
hours  nearly  all  dust  and  most  of  the  bacteria 
will  have  settled  to  the  lowest  resting-place. 
Whether  the  air  shall  be  permanently  rid  of  its 
living  or  inert  dust  particles  or  not,  will  of 
course  depend  upon  the  measures  which  are 
resorted  to  in  the  familiar  performances  of 
sweeping  and  dusting,  of  which  more  by  and  by. 

A  good  many  of  these  facts  which  have  been 
just  set  down  in  regard  to  dust,  are  embodied 


DUST  AND  ITS  DANGERS.  35 

in  the  lore  of  the  intelligent  house-keeper, 
scientific  studies  having  simply  given  precision 
to  common  beliefs  and  revealed  certain  quali- 
ties in  dust,  which  may  possibly  render  it  of 
greater  significence  than  an  annoying  and  an 
omnipresent  form  of  dirt. 


CHAPTER  VI. 

THE    SAFEGUARDS    OF   THE    BODY    AGAINST    IN- 
HALED   DUST. 

HAVING  now  gathered  together  a  con- 
siderable number  of  facts  about  the 
distribution  in  the  air  of  dust  particles  and 
among  them  of  living  germs,  we  are  ready  to 
consider  their  significance — if  they  have  any — 
to  human  beings,  who  must  live  in  and  breathe 
this  more  or  less  dust-laden  air. 

The  average  amount  of  air  which  a  healthy 
grown  person  takes  in  at  each  breath  has  been 
estimated  to  be  about  one  half  a  litre  (about 
30  cubic  inches).  We  have  seen  from  our 
various  analyses  of  the  air  of  different  places  in 
and  about  New  York,  under  ordinarily  favor- 
able conditions,  that  the  number  of  living 
germs  in  10  litres  of  air  varies  from  1 1  to  376. 
So  that  basing  our  estimate  upon  these  studies 

36 


DUST  AND  ITS  DANGERS.  37 

of  the  air  in  this  city,  with  every  twenty 
breaths  one  may  take  into  his  body,  depending 
upon  where  he  is  all  the  way  from  u  to  376 
living  micro-organisms,  together  with  a  variable 
amount  of  inorganic  dust. 

The  number  of  living  germs  which  the  New 
York  citizen  is  liable  to  be  forced  to  take  into 
his  body,  when  the  streets  are  dry  and  the 
wind  blowing,  or  when  the  dry  filth  is  being 
stirred  up  by  careless  street-cleaning  proced- 
ures, it  would  be  a  difficult  and  a  thankless 
task  to  tell. 

Now  it  has  been  learned,  not  only  from  com- 
mon experience  but  from  long  series  of  careful 
experiments,  that  the  solid  particles  which  we 
breathe  in  with  the  air  either  through  the  nose 
or  mouth  do  not  come  out  with  the  expired  air, 
but  are  retained  on  the  moist  surface  upon 
which  the  air  impinges  going  in  and  coming 
out.  These  foreign  particles  floating  in  the 
inspired  air  are  caught  largely  in  the  nose  or 
mouth  or  upper  throat,  while  a  certain  number 
pass  down  into  the  air-tubes  and  lungs.  A 
large  part  of  this  foreign  material  may  be  dis- 
charged from  the  nose  where  it  is  caught  in  the 


38  DUST  AND  ITS  DANGERS. 

mucous  which  that  organ  secretes  when  irri- 
tated. 

A  very  considerable  proportion  of  the  in- 
breathed foreign  material  gets  into  the  mouth 
and  may  be  spat  out  or  swallowed. 

The  floating  material  which  is  carried  past 
the  well-guarded  portals  of  the  lungs  and 
enters  the  windpipe  and  bronchial  tubes  and 
lodges  on  their  moist  walls  finds  here  a  most 
efficient  arrangement  for  its  expulsion.  Here 
is  placed,  completely  lining  the  tubes,  an  army 
of  thoroughfare-cleansers  composed  of  individ- 
uals who  are  not  in  politics,  who  have  no  vote, 
and  who  present  to  us  the  unwonted,  and  at 
first  puzzling,  spectacle  of  street-cleaners  whose 
business  seems  to  be  to  clean  the  streets. 
Completely  lining  the  larger  air-tubes  like 
a  mosiac,  are  myriads  of  tiny  cells  shaped 
something  like  a  narrow  short  club  and  set 
upon  end  side  by  side.  Projecting  from  the 
free  ends  of  each  one  of  these  cells  is  a  number 
of  very  minute  hairs,  so  that  the  whole  cell 
looks  something  like  a  short  club  with  a  beard 
growing  from  one  end  (see  Fig.  3).  The 
whole  inner  surface  of  these  air-tubes,  then,  is 


DUST  AND  ITS  DANGERS. 


39 


lined  with  these  delicate  hairs  which  are  called 
cilia. 

Now,  these  myriads  of  cilia,  year  in  and  year 
out,  day  and  night,  while  life  lasts,  are  con- 
stantly swinging  their  free  ends  back  and  forth, 
bending  as  they  recover,  and  then  with  a  quick 


FIG.    3. — CILIATED     CELLS     FROM    THE    LARGE    AIR-TUBES    OF    THE 
HUMAN  LUNGS,    SEEN   FROM   THE   SIDE.      HIGHLY  MAGNIFIED. 

snap  forward  so  that  any  small  object  which 
lodges  on  the  walls  of  the  larger  air-tubes — 
since  all  the  cilia  act  in  rhythm — is  swept  up- 
wards toward  the  mouth,  away  from  the  peril- 
ously delicate  and  sensitive  lungs. 

The  movement  of  these  cilia  is  less  vigorous 
when  the  body  is  quiet,  as  in  sleep,  increasing 


DUST  AND  ITS  DANGERS. 


in  rapidity  and  force  when  the  body  is  active. 
Almost  every  one  has  noticed  that  shortly  after 
rising  more  or  less  mucus  or  "  phlegm  "  is  apt 
to  come  up  into  the  throat.  This  is  because  the 
increasing  vigor  of  the  ciliary  movement,  as 
one's  general  activity  increases,  sweeps  up  the 
accumulation  which  the  comparative  quiescence 
of  the  night  has  allowed  to  form. 

It  is  a  curious  thing  that  these  humble  but 
energetic  little  members  of  the  cell  communi- 
ties which  make  up  the  body  are  apparently  the 
last  elements  to  die  when  what  we  sometimes 
call  the  vital  forces  no  longer  act.  The  breath 
ceases,  the  heart  flutters  and  is  still,  the  blood 
ebbs  and  flows  a  little  here  and  there,  the  last 
definite  nerve  impulses  express  themselves  as 
now  one  now  another  muscle  quivers  or  feebly 
and  fitfully  contracts,  but  still  these  wonderful 
little  cilia  keep  swinging  on  sometimes  for 
hours  after  all  trace  of  what  we  have  called 
life  has  disappeared,  and  when  these  too  at 
last  are  still,  and  not  till  then,  is  life  in  the 
body  totally  extinct. 

There  is  another  very  curious  arrangement 
in  the  air  passages  for  the  disposition  of  small 


DUST  AND  ITS  DANGERS.  4! 

foreign  bodies  which  are  breathed  into  the 
lungsv.  There  are  certain  cells  in  the  body 
which  seem  to  have  nothing  in  particular  to  do 
on  ordinary  occasions  but  to  float  about  on  the 
blood  tides  or  wander  through  the  various 
channels  and  crevices  of  the  tissues  watching 
other  cells  work.  Sometimes  they  come  out 
and  air  themselves  in  the  bronchial  tubes  or  in 
the  tiny  air-chambers  which  make  up  the  body 
of  the  lungs.  But  the  moment  these  cells 
come  upon  a  foreign  particle  from  without  or 
upon  a  fragment  of  worn-out  tissue  anywhere 
in  the  body  they  pounce  upon  it,  wrap  them- 
selves around  it,  and  either  digest  or  destroy 
it  or  carry  it  off  to  some  safe  place  of  deposit, 
either  inside  the  tissues  or  without.  Now  these 
humble  scavenger  cells  are  usually  quite  abun- 
dant in  the  air  passages,  where  they  often  take 
up  dust  particles  of  one  kind  or  another,  and 
victims  to  their  zeal  are  not  infrequently  swept 
with  their  booty  by  the  ciliated  cells  up  and 
away  into  the  mouth.  A  good  deal  of  lore  has 
accumulated  about  these  little  wandering  scav- 
engers of  the  body  and  they  seem  to  be  of  great 
importance  in  many  ways.  But,  in  spite  of 


42  DUST  AND  ITS  DANGERS. 

their  usefulness  and  the  various  beneficent 
things  which  they  do,  scientific  men  have  seen 
fit  to  make  them  bear  the  added  burden  of  the 
name  of  phagocytes^ 

But  to  return  to  our  dust  particles.  In  spite 
of  all  the  safeguards  with  which  our  lungs  are 
furnished  against  the  entrance  of  foreign 
bodies,  into  their  deep  and  delicate  recesses 
and  through  them  into  the  blood,  a  considerable 
number  of  dust  particles  of  one  kind  or  another 
do  get  in  and  permanently  lodge  upon  those 
walls  of  the  delicate  breathing  chambers  in  the 
lungs,  which  are  beyond  the  protecting  agency 
of  the  ciliated  cells.  Now  right  in  the  walls 
of  these  tiny  air-chambers  of  the  lungs,  where 
the  blood  is  separated  from  the  inbreathed  air 
only  by  a  film,  one  of  the  most  important  and 
subtle  of  the  vital  process  goes  on,  upon  which 
the  continued  purity  and  virtue  of  the  blood 
depends.  Here  the  blood  gives  up  the  car- 
bonic acid  and  water  which  it  has  gathered  in 
its  journey  around  the  system,  and  takes  in  its 
fresh  supplies  of  oxygen. 

Although  persons  who  habitually  work  in 
very  much  dust-laden  air  are  liable  to  pul- 

1  See  "  The  Story  of  the  Bacteria," 


DUST  AND  ITS  DANGERS.  43 

monary  disease  caused  by  the  lodgment  in 
their  lungs  of  foreign  particles  of  one  kind  or 
another,  and  furthermore,  although  even  com- 
paratively small  amounts  of  foreign  particles  in 
the  lung  tissue  cannot  fail  to  be  undesirable 
additions  to  those  organs,  still  it  is  a  fact  that 
the  lungs  do  establish  for  themselves  a  consid- 
erable degree  of  what  we  call  tolerance  of  for- 
eign particles  lodged  in  their  tissues.  That  is 
to  say,  there  may  be  a  good  deal  of  accumula- 
tion of  foreign  material  in  the  lungs  without 
any  appreciable  interference  with  the  health, 
because  the  body  here,  as  in  many  other  ways, 
has  the  power  of  adapting  itself  to  unusual  and 
even  harmful  conditions. 

In  fact,  the  lungs  of  nearly  all  adults  who  live 
under  what  we  call  civilized  conditions,  that  is, 
in  houses  with  considerable  smoke  and  dust  in 
the  air,  in  cities  which  have  street-cleaning  done 
for  political  purposes  only,  or  in  manufacturing 
regions  where  there  is  much  smoke,  instead  of 
being  of  a  delicate  spotless  pink  color  are  dotted 
all  over  with  spots  and  streaks  and  patches  of 
inhaled  dust-particles  which  the  body  has  not 
been  able  to  get  rid  of  but  has  stowed  away 


44  DUST  AND  ITS  DANGERS. 

permanently  in  the  tissues  in  such  situations  as 
will  least  interfere  with  the  action  of  the  lungs 
(see  Fig.  4).  Here  it  remains  as  long  as  life 
lasts. 


FIG.  4. — PIGMENTATION  OF  THE  LUNG  FROM  INHALED  DUST. 

A  small  portion  of  the  surface  of  an  adult  human  lung  which  has 
become  pigmented  by  the  inhalation  of  dust.  This  drawing  was 
made  not  from  the  lung  of  a  coal  miner  or  one  who  had  lived  in 
especially  smoky  or  dusty  places,  but  from  that  of  an  individual  ex- 
posed to  the  ordinary  conditions  of  in-door  city  life. 

But  we  have  not  yet  finished  with  the  safe- 
guards which  the  body,  has  placed  for  itself 
against  inhaled  dust.  For,  however  success- 


DUST  AND  ITS  DANGERS.  45 

fully  the  lungs  may  stow  it  away  in  consider- 
able quantities,  there  is  a  very  curious  provision 
against  its  further  entrance  to  and  distribution 
in  the  body.  This  is  the  way  that  is  provided 
against.  As  the  blood  circulates  through  the 
lungs  as  well  as  in  every  other  part  of  the  body, 
a  small  amount  of  its  fluid  part,  conveying  an 
abundance  of  nutriment,  oozes  out  through  the 
walls  of  the  vessels  into  all  the  minute  clefts  and 
crannies  of  the  tissues  where  the  cells  lie  and 
bathes  and  nourishes  them.  Now,  having  done 
this,  the  nutritive  fluid — which  we  call  lymph — 
is  gradually  collected  into  a  series  of  irregular 
narrow  vessels  which  open  into  large  and  still 
larger  trunks  until  finally  it  is  poured  back  into 
the  blood,  of  which  it  again  becomes  a  part. 

If  this  lymph  which  has  searched  out  every 
remotest  corner  of  the  body  to  which  it  was 
distributed  should  have  become  contaminated 
or  polluted  by  any  harmful  or  foreign  material 
which  it  had  come  across  in  the  tissues,  it  would 
carry  it  straight  back  and  pour  it  into  the  blood, 
where  it  might  cause  dire  results,  since  the 
blood  is  an  extremely  important  and  delicate 
juice.  But  fortunately  the  lungs,  as  well  as 


46  DUST  AND  ITS  DANGERS. 

several  other  important  organs  of  the  body,  are 
provided  with  a  series  of  very  efficient  filters, 
through  which  the  lymph  has  to  pass  in  its 
transit  toward  the  blood  current  with  which 
it  is  to  mingle.  Now  several  of  these  living 
filters,  which  we  call  "  lymph-glands/'  little 
reddish-white  bodies,  are  grouped  deep  in  the 
chest  at  the  root  of  the  lungs,  and  are  so 
very  effective  that,  although  the  lungs  may 
be  crowded  with  inhaled  dust  particles  stored 
away  permanently  in  out-of-the-way  places,  and 
the  lymph  filters  may  finally  become  themselves 
as  black  as  your  hat  from  its  accumulation 
(see  Fig.  5)  the  dust  rarely  gets  through  them 
and  into  the  blood  or  other  parts  of  the  body. 

Thus  far,  in  considering  the  safe-guards  of 
the  body  against  inhaled  dust,  we  have  been 
thinking  only  of  those  lifeless  particles  of  one 
kind  or  another  which  make  up  the  inorganic 
part  of  dust.  How  is  it  with  bacteria, — with 
those  dust  particles  which  are  quite  inert  when 
dry  in  the  dust,  but  which,  when  the  moisture 
and  warmth  and  food  they  need  are  furnished, 
may  grow  and  multiply  with  great  rapidity. 


DUST  AND  ITS  DANGERS.  47 

In  answer  to  this,  it  should  be  said  that  not 
only  does  the  body  afford  the  same  safe-guards 
against  these  living  germs  as  against  other 
dust  particles,  as  just  described,  but  most  of 
the  different  kinds  of  germs  which  are  floating 


FIG.  5. — DUST  FILTERS  IN  THE  LUNG DEEPLY  PIGMENTED. 

A  drawing  of  one  lobe  of  a  human  lung,  showing  the  lymph  filters 
(lymph-glands)  at  one  side,  which  have  caught  so  much  inhaled  dust 
in  their  meshes — thus  keeping  it  out  of  the  blood — as  to  have  become 
almost  totally  black.  These  glands  are  naturally  of  a  light-pink  color. 

in  the  air  do  not  grow  in  the  human  body  in 
any  appreciable  degree ;  the  soil  is  not  good 
for  them.  Some  do  not  find  in  the  nose,  or 
the  mouth,  or  the  lungs,  the  proper  food  or 
conditions  which  they  need,  others  are  actually 
killed  off  sooner  or  later,  either  owing  to  some 


48  DUST  AND  ITS  DANGERS. 

quality  in  the  body  juices  which  is  quite  in- 
imical to  their  life,  or  by  those  vigilant  phago- 
cytes which  we  have  noticed  above — or  per- 
haps in  other  ways  which  we  do  not  yet  know 
any  thing  about.  The  germs  which  are  swal 
lowed  after  being  caught  in  the  nose  or  mouth 
from  the  inspired  air,  or  swept  up  from  the  air- 
tubes  by  the  ciliated  cells,  are,  for  the  most 
part,  soon  deprived  of  life  by  the  digestive 
fluids. 

There  is  one  species  of  bacteria  which  we 
are  to  learn  more  about  presently  (the  tubercle 
bacilli)  which,  when  they  lodge  in  the  tissues, 
sometimes  stimulate  the  cells  near  them  which 
multiply  and  build  up  a  dense  enclosing  wall 
about  the  intruding  germs,  so  that  these  be- 
come imprisoned  in  a  little  bag  or  sac  in  the 
body,  and  can  neither  get  away,  nor  spread,  nor 
do  further  damage.  They  are  sometimes  so 
cut  off  from  nutriment,  that  they  die,  or  at 
best  sustain  for  some  time,  a  poor  and  meagre 
existence.  (See  Fig.  6,  p.  69.) 

There  are  individual  conditions  of  the  body 
in  which  it  affords  a  most  obstinate  resistance 
to  the  incursions — that  is,  the  growth  of  bac- 


DUST  AND  ITS  DANGERS.  49 


teria  within  it.  There  are  other  conditions  in 
which  it  seems  fairly  predisposed  to  their 
growth  and  ravages.  What  the  nature  of  the 
conditions  is,  which  in  one  individual  or  at  one 
time  confers  immunity  to  harmful  bacterial 
growth,  and  at  another  renders  it  predisposed 
to  their  ravages,  we  do  not  know.  But  very 
zealous  workers  are  busy  with  the  problem,  and 
we  may  hope  in  due  time  to  get  light  and  con- 
fidence in  this  obscure  field,  where,  we  can  now 
but  feebly  grope. 

4 


CHAPTER  VII. 

THE    REAL   SIGNIFICANCE   OF   DUST   IN    ITS   RELA- 
TION  TO    DISEASE. 

BUT  why  then,  it  may  be  asked,  all  these 
sinister  allusions  to  the  danger  of  dust, 
if,  as  we  have  seen  in  the  last  chapter,  most  of 
it  is  caught  before  it  gets  into  the  lungs,  and 
that  which  does  get  in  is  disposed  of  in  such 
clever  ways  ?  This  question  brings  us  at  last 
face  to  face  with  the  gist  of  the  whole  matter. 
The  body  does  rid  itself  of  a  great  deal  of  the 
inhaled  inorganic  dust  which  lodges  in  the  nose 
and  mouth  and  air-tubes  of  the  lungs.  It  does 
do  the  best  it  can  to  dispose  of  that  which  is 
permanently  stowed  away  in  the  lung  tissues 
themselves.  It  does  without  more  ado  kill  out- 
right or  otherwise  make  way  with  most  of  the 
living  germs.  But  when  all  this  is  accomplished 
there  still  remain  certain  important  ways  in 


DUST  AND  ITS  DANGERS.  51 

which  dust  particles  of  one  kind  or  another 
may  do  serious  harm  to  human  beings. 

We  shall  do  well  in  considering  these 
harmful  effects  of  dust  to  separate  in  our 
thought  its  inorganic  from  its  germ  ingredi- 
ents. 

The  inorganic  elements  of  dust  when  present 
in  large  quantities  in  the  inhaled  air  may,  as 
we  have  seen  above,  cause  well-defined  disease 
of  the  lungs  by  the  persistent  irritation  which 
they  induce.  But  as  it  is  only  under  excep- 
tional conditions,  as  among  coal-miners  and 
grinders  and  other  workers  in  confined  places 
where  these  solid  particles  are  set  free  in  great 
numbers  that  this  occurs,  we  need  not  con- 
sider them  here.  Very  moderate  amounts 
of  dust  particles  in  sensitive  persons  cause 
such  a  degree  of  irritation  of  the  respiratory 
organs  as  either  to  deprive  them  of  robust 
health  or  predispose  them  to  the  aquirement 
of  various  diseases  which  with  unirritated 
lungs  they  would  readily  resist. 

There  is  no  doubt  that  a  great  deal  of 
misery,  if  not  positive  disease,  is  caused  by  the 
inhalation  of  dust  in  the  persistent  coughs  and 


52  DUST  AND   ITS  DANGERS. 

more  persistent  protean  catarrhs  with  which  so 
many  persons  otherwise  healthy  are  burdened. 

Then  again  dust  may  produce  much  distress 
when  not  inhaled,  by  irritating  the  eyes  to  such 
a  degree  as  to  cause  great  discomfort,  if  not 
positive  disease. 

Smoke,  which  is  a  growing  evil  in  many 
cities,  is  a  kind  of  dust  which,  though  not  so 
obviously  pernicious  as  some  other  forms,  is 
still  capable  of  doing  serious  damage  in  the 
long  run  to  the  delicate  respiratory  organs. 
Improperly  managed  motor  vehicles  which 
smoke,  are  responsible  for  injury  to  citizens 
in  this  way  and  should  be  treated  as  nuisances 
by  health  authorities. 

As  to  the  bacteria  about  which  our  main  in- 
terest centres,  there  are  unfortunately  a  few 
species  which,  when  they  once  find  lodgement 
in  one  place  or  another  in  the  organs  of 
respiration,  may  grow  and  multiply,  and  suc- 
cessfully resisting  all  the  protective  agencies  of 
the  body,  set  up  distinct,  persistent  and  even 
fatal  disease.  Those  forms  of  bacteria  which 
can  or  in  these  regions  commonly  do  this,  are 
insignificant  in  number  in  comparison  with  the 


DUST  AND  ITS  DANGERS.  53 

harmless  species  with  which  dust  is  usually 
swarming.  But  few  as  they  are  they  have  an 
extreme  significance.  If  it  were  not  for  these 
few  species  of  disease-producing  bacteria  most 
people  could  perhaps  afford  to  be  as  indifferent 
as  they  are  to  dust  and  its  dangers. 

We  have  seen  that  the  large  numbers  of 
common  bacteria  which  are  omnipresent  in  the 
air  are  growing  all  about  us  and  get  into  the 
dust  in  many  ways  which  we  not  only  cannot 
control  but  do  not  very  much  care  to  control, 
since  in  moderate  numbers  they  are  essentially 
harmless,  or  at  least  do  only  such  damage  as 
other  inorganic  dust  particles  may  do.  But 
with  the  bacteria  which  cause  disease  the  case 
is  entirely  different.  They  do  not  flourish 
apart  from  the  bodies  of  men  and  animals. 
They  may  remain  alive  for  a  good  while  out- 
side of  the  body,  and  some  of  them  may  grow 
a  little  under  some  few  special  conditions. 
Some  of  them  are  frequently  present  in  the 
healthy  human  body. 

But  after  all  when  we  seek  for  the  active 
breeding-places  and  sources  of  distribution  of 
the  bacteria  which  frequently  cause  disease  in 


54  DUST  AND  ITS  DANGERS. 

man  in  this  region,  we  find  that  they  are  the 
bodies  of  persons,  and  occasionally  animals, 
suffering  from  the  diseases  which  the  bacteria 
cause.  It  is  the  presence  of  these  bacteria  in 
large  numbers  given  off  from  the  body,  which 
makes  these  diseases  what  we  call  infectious 
or  communicable. 

If  we  could  completely  isolate  all  those  per- 
sons or  animals  who  are  at  the  present  moment 
harboring  the  few  known  species  of  bacteria 
which  produce  disease  in  man,  such  diseases 
could  be  largely  stricken  from  the  list  of 
human  ills.  U nless  they  were  lighted  up  afresh 
by  some  of  the  discharged  material  which  on 
walls,  or  garments,  or  in  the  soil,  or  in  the 
aerial  dust,  still  retained  vitality.  At  any  rate, 
if  we  could  be  certain  that  the  discharged 
material  from  such  sick  people  were  immedi- 
ately destroyed  we  should  be  able  to  limit 
within  narrow  bounds  those  diseases  which  to- 
day carry  off,  prematurely,  the  larger  part  of 
those  who  do  not  die  of  injuries  or  of  old  age. 
They  are  thus,  at  least  ideally,  preventible 
diseases. 

But  this  matter  of  preventing  the  spread  of 


DUST  AND  ITS  DANGERS.  55 

bacterial  disease  by  means  of  dust  is  of  such 
extreme  importance  that  we  must  be  very  cer- 
tain that  we  are  dealing  with  facts  and  not  with 
conjectures,  when  we  consider  the  relationship 
one  to  the  other.  Let  us  then  get  the  facts 
together  first. 

There  is  a  large  number  of  diseases  which 
physicians  call  infectious ;  these  all  have  cer- 
tain ways  of  manifesting  themselves,  certain 
family  traits  which  would  justify  this  grouping 
of  them  together  even  without  a  knowledge  of 
the  particular  agent  which  causes  them.  The 
more  important  of  these  infectious  diseases 
are  :  consumption  or  tuberculosis,  diphtheria, 
small-pox,  yellow-fever,  Asiatic  cholera,  ty- 
phoid-fever, scarlatina,  measles,  pneumonia, 
influenza,  and  blood-poisoning.  There  are 
others  of  less  frequent  occurrence  in  this  re- 
gion, which  we  need  not  mention  here. 

Now  within  the  past  few  years  we  have  found 
out  positively  and  without  question  that  the 
particular  and  exclusive  agent  which  causes 
some  of  these  diseases  is  one  or  other  form  of 
bacteria.  Each  disease  has  its  special  form  of 
bacteria,  without  which  it  can  by  no  possibility 


56  DUST  AND  ITS  DANGERS. 

exist.  The  particular  species  causing  some  of 
these  diseases  have  been  isolated  and  studied 
and  experimented  upon  in  so  many  ways  and 
by  so  many  workers  that  we  feel  perfectly  cer- 
tain about  them.  Among  such  diseases  are  : 
consumption,  pneumonia,  typhoid-fever,  Asia- 
tic cholera,  influenza,  some  forms  of  blood- 
poisoning,  diphtheria,  and  many  "colds." 

Concerning  the  kinds  of  germs  which  cause 
some  other  of  the  infectious  diseases  we  are 
yet  in  doubt.  They  are  no  doubt  also  caused 
by  some  form  of  micro-organism  or  germ,  but 
what  it  may  be  and  -how  it  acts  is  not  fully 
determined. 

Among  those  infectious  diseases  the  exact 
causes  of  which  have  not  yet  been  made  out 
may  be  mentioned  small-pox,  yellow-fever, 
measles,  and  scarlatina. 

Now  to  make  a  long  story  short,  and  to  give 
precision  to  our  theme,  I  purpose  to  limit  this 
study  of  the  relationship  of  dust  to  disease 
largely  to  that  one  bacterial  malady  which  is 
most  important,  which  we  know  much  about 
and  which  we  can  do  most  to  prevent,  namely, 
consumption  or  tuberculosis. 


DUST  AND  ITS  DANGERS.  57 

Many  of  the  conclusions  to  which  we  shall 
be  forced,  and  many  of  the  practical  hints  as 
to  personal  action  which  we  shall  gain,  apply 
equally  to  some  of  the  other  bacterial  diseases. 

But  most  of  these  are  apt  to  make  people 
early  and  more  or  less  seriously  ill,  and  so 
they  come  under  the  charge  of  the  physician, 
who  should  on  the  spot  suggest  measures  to 
prevent  their  spread.  On  the  other  hand,  per- 
sons affected  with  consumption  very  frequently 
go  about  for  weeks  and  months  among  their 
fellows,  always  liable,  through  ignorance  or 
carelessness,  to  transmit  the  disease-producing 
germs  to  others,  as  well  as  constantly  repoi- 
son  themselves,  and  thus  greatly  diminish  the 
chances  of  recovery  which  they  might  other- 
wise anticipate. 

It  is  most  important  then  that  everybody 
should  have  some  definite  knowledge  about 
the  cause  and  mode  of  spread  of  consumption, 
since  it  spares  no  age  and  no  class  and  is  the 
most  widespread  and  fatal  of  all  the  diseases 
known  to  man,  and  is  in  large  degree,  could 
we  but  secure  thorough  cleanliness  in  the  air 
we  breathe  and  the  food  we  eat,  a  distinctly 
preventible  disease. 


CHAPTER  VIII. 

CONSUMPTION    AND    THE    WAYS    IN    WHICH    IT    IS 
SPREAD    BY    DUST. 

THE  germ  which  causes  consumption  or 
tuberculosis  is  a  minute  slender  rod-like 
body  about  one  ten-thousandth  of  an  inch  in 
length,  and  is  called  the  Bacillus  tuberculosis. 
It  does  not  grow  in  nature  outside  of  the  bodies 
of  men  and  a  few  species  of  warm-blooded 
animals.  It  may,  however,  remain  alive  for 
a  long  time  when  dry  as  in  the  soil  or  air. 

In  the  bodies  of  some  animals  and  in  the 
bodies  of  many  men  it  does  not  ordinarily 
flourish  or  even  grow  at  all,  for  reasons  which 
we  do  not  understand.  The  proper  tempera- 
ture may  be  present  and  moisture  and  nutritive 
material  in  abundance,  but  for  some  unknown 
reason  it  will  not  grow.  There  are  other  in- 
dividuals and  other  animals  which  seem  to 


DUST  AND  ITS  DANGERS.  59 

furnish  the  unknown  conditions,  and  in  them 
the  bacillus  grows  more  or  less  rapidly ;  such 
persons  or  animals  are  said  to  be  predisposed 
to  the  disease — consumption. 

A  great  deal  of  misery  and  wearing  appre- 
hension have  been  caused  in  the  years  which  are 
past  by  the  widespread  notion  that  consump- 
tion may  be  inherited.  Modern  researches 
show  that  this  notion  is  not  well-founded.  It 
is  true  that  there  is  a  subtle  make-up  of  the 
body  cells  in  certain  persons,  some  entirely 
mysterious  nutritive  condition,  which  renders 
their  bodies  especially  favorable  for  the  growth 
of  the  tubercle  bacillus,  and  that  this  indefinite 
and  ill-understood  peculiarity  may  be  inherited. 
But  that  is  all.  If  the  tubercle  bacillus  can 
be  kept  away  from  them,  even  predisposed 
persons  cannot  get  consumption,  for  this  dis- 
ease without  the  bacillus  cannot  exist,  and  the 
bacillus  does  not  as  far  as  we  know  pass  from 
the  mother  to  the  unborn  child.  But  this  so- 
called  predisposition  is  not  always  inherited ; 
it  may  be  and  often  is  acquired,  sometimes  in 
ways  which  we  know  about,  sometimes  in  ways 
which  we  do  not  fully  understand. 


60  L>(JST  AND  ITS  DANGERS. 

When  the  tubercle  bacilli  get  into  the  bodies 
of  predisposed  individuals  and  begin  to  grow 
they  stimulate  the  tissues  about  them  so  that 
little  new-formed  masses  of  cells  appear  about 
and  among  the  growing  germs.  These  cell 
masses  are  called  tubercles.  Sometimes  larger 
masses  of  new  cells  are  developed,  which  re- 
place considerable  portions  of  the  tissues  and 
organs  in  which  the  bacilli  have  lodged.  After 
a  time,  especially  in  the  lungs,  the  new-formed 
tissue,  containing  sometimes  enormous  num- 
bers of  the  living  tubercle  bacilli,  gradually 
disintegrates  or  breaks  down,  and  this  broken- 
down  germ-laden  material  may  then  be  dis- 
charged with  the  mucus  from  the  bronchial 
tubes  day  after  day  in  considerable  quantities 
for  months  or  even  years,  in  the  expectoration, 
new  bacilli  forming  as  fast  as  the  old  are  dis- 
charged and  sometimes  even  much  faster. 

Tuberculosis  may  have  its  seat  in  other  parts 
of  the  body  than  the  lungs,  but  with  the  lung 
affection  alone  we  are  now  concerned. 

This  then  is  the  great  primary  fact  which  is 
of  extremest  significance  to  us  in  our  present 
study  ;  namely,  that  every  person  suffering 


DUST  AND  ITS  DANGERS.  6 1 

from  consumption  of  the  lungs  may  be  expec- 
torating every  day  myriads  of  living  and  vir- 
ulent tubercle  bacilli,  and  that  the  life  and 
virulence  of  all  of  these  bacilli  are  not  destroyed 
by  prolonged  drying. 

Now  leaving  this  fact  for  a  moment,  let  us 
see  how  common  a  disease  consumption  or 
tuberculosis  is  after  all. 

From  one  seventh  to  one  fourth  of  all  the 
people  who  die  are  carried  off,  most  of  them 
prematurely,  by  this  disease.  In  Europe  about 
one  million  persons  die  each  year  from  con- 
sumption that  is  about  3,000  every  day. 

In  the  United  States  the  deaths  are  counted 
by  hundreds  of  thousands.  Neither  old  nor 
young  are  spared,  but  the  average  age  at  death 
has  been  estimated  at  thirty-seven.  Let  him 
who  has  watched  the  progress  of  this  insidious 
disease  in  but  a  single  case,  imagine  if  he 
can  the  misery  and  pain  which  these  figures 
represent. 

The  disease  is  considerably  less  frequent  in 
some  regions  and  countries  than  in  others,  but 
everywhere  where  men  live  together  in  large 
numbers,  or  live  under  bad  sanitary  conditions 


62  DUST  AND  ITS  DANGERS. 

in-doors,  this  disease  claims  its  numerous  vic- 
tims when  once  it  gains  a  foothold. 

Our  attention  is  not  ordinarily  called  to  the 
large  numbers  of  persons  who  sicken  and  die 
from  consumption,  because  we  have  become  so 
accustomed  to  it  that  it  is  taken  as  a  matter  of 
course, — one  of  the  inevitable  ills  of  life.  When 
yellow-fever  or  small-pox  or  Asiatic  cholera 
threaten  to  spread  among  us,  we  are  on  our 
guard  at  once,  and  from  the  medical  profession 
and  the  press  come  such  warnings  that  no 
pains  are  spared  in  public  or  in  private  to  stay 
their  progress.  And  yet  the  number  of  victims 
of  these  occasional  and  dramatic  epidemics  is 
quite  insignificant  as  compared  with  those  of 
our  omnipresent  consumption. 

We  dread  small-pox  and  carefully  guard 
ourselves  against  its  spread,  but  in  the  State 
of  New  Jersey,  which  is  typical  of  many  others, 
in  1904  there  were  one  hundred  and  fifty  times 
as  many  deaths  from  consumption  as  from 
small-pox. 

We  find  in  the  report  of  the  Health  Depart- 
ment of  New  York  City  for  the  year  1907, 
that  in  this  town  out  of  79,205  deaths  from 


AND  ITS  DANGERS.  63 

all    causes,     8,000    were    from    consumption. 

All  over  the  world  the  story  is  much  the 
same — enormous  losses  from  a  well  defined 
clearly  understood  preventable  disease.  Some 
of  the  totals  are  certainly  impressive. 

It  is  estimated  that  in  the  year  1907  not 
less  than  190,000  deaths  occurred  in  the  United 
States  from  some  form  of  tuberculosis. 

Of  all  the  classified  causes  of  death,  tuber- 
culosis is  the  most  important.  In  the  mortality 
statistics  of  the  United  States  Census  Bureau 
for  1907  will  be  found  a  sinister  summary  of 
deaths  from  1901  to  1905.  In  a  total  of 
2,648,149  deaths,  there  are  314,173,  which  is 
11.9  per  cent,  due  to  tuberculosis. 

These  are  the  bald  relentless  records  of  the 
deaths.  But  who  shall  adequately  picture,  or 
even  remotely  conceive,  the  shattered  ambi- 
tions, the  long  weary  hours  of  distress  and 
suffering  and  struggle,  the  slow  weeks  and 
months,  lighted  fitfully  now  and  then  by  gleams 
of  fictitious  hope,  which  lead  to  the  last  long 
release.  And  what  shall  be  said  of  the  deso- 
lated homes  and  scattered  families,  and  pov- 


64  DUST  AND  ITS  DANGERS. 

erty  and  want  and  crime  which  among  the 
poor  are  wont  to  cluster  about  and  to  follow 
such  premature  and  lingering  death  ?  Probably 
the  actual  suffering  and  distress  caused  by  all 
other  diseases  put  together  is  far  less  than 
that  which  in  one  way  or  another  is  associated 
with  consumption. 

Now  where  do  all  these  people  get  this  most 
widespread  disease  ?  How  do  they  become 
infected  ?  Where  do  the  living  bacilli  of  this 
particular  species  come  from  which  get  into 
their  bodies  ?  They  do  not  grow  at  the  tem- 
perature of  the  air  out-of-doors.  There  are  no 
lurking-places  for  them  in  nature  apart  from 
those  men  or  animals  who  have  the  disease. 

Plant  them  artificially  with  other  common 
bacteria  in  tubes  in  the  laboratory  and  they 
die ;  they  succumb  in  the  struggle  for  exist- 
ence with  the  harmless  species  of  the  earth  and 
water  and  air.  They  are  soon  killed  by  sun- 
light and  many  are  destroyed  by  drying. 

Inasmuch  as  tuberculosis  of  cattle  is  a  very 
common  disease  in  this  country,  there  is  every 
reason  for  believing  that  the  infection  often 
enough  occurs  through  the  use  of  uncooked 


DUST  AND  ITS  DANGERS.  65 

meat  or  milk.  That  the  consumptive  mother 
may  infect  the  nursing  child  with  its  food  has 
been  abundantly  proven.  There  are  cases  in 
which  the  tubercle  bacilli  get  into  the  blood 
and  are  distributed  to  all  parts  of  the  body, 
setting  up  such  innumerable  foci  of  disease 
that  the  individual  soon  succumbs  to  the 
violence  of  the  poison. 

But  after  all,  the  prevailing  seat  of  consump- 
tion being  in  the  lungs,  the  most  natural 
supposition  is  that  the  larger  proportion  of 
consumptive  people  become  infected  through 
the  inhaled  air. 

Now,  as  has  been  absolutely  proven  over 
and  over  again,  in  almost  all  populous  regions, 
both  out-of-doors  and  in-doors,  tubercular  per- 
sons may  be  discharging  thousands  of  living 
tubercle  bacilli  every  time  they  spit  out  mate- 
rial from  their  lungs  upon  the  streets,  or  upon 
the  floors,  or  wherever  it  can  dry  and  mingle 
with  the  dust.  If  not  all  the  tubercle  bacilli 
are  easily  killed  by  drying,  as  has  been  proven, 
have  we  not  a  sufficient  explanation  of  the  way 
in  which  the  infection  of  tuberculosis  becomes 
so  widely  and  perpetually  spread  ? 


66  DUST  AND  ITS  DANGERS. 

If  this  be  true, — that  tuberculosis  is  spread 
by  the  breathing  in  of  tubercle  bacilli  in  the 
dust  of  the  air,  then,  it  may  be  said,  we  ought 
to  be  able  to  find  these  particular  germs  in 
the  dust  of  rooms  inhabited  by  consumptives. 
This  is  by  no  means  an  easy  task,  because  our 
means  of  identifying  this  germ  are  rather  com- 
plex, and  require  for  their  execution  much  time 
and  skill.  But  notwithstanding  this,  Cornet, 
in  Berlin,  has  over  and  over  again,  in  the  dust 
high  up  on  the  walls  of  consumptive  wards  of 
hospitals,  in  the  dust  of  private  houses,  and 
hotel  rooms  occupied  by  consumptive  patients, 
found  living  virulent  tubercle  bacilli.  But  he 
found  these  only  in  cases  in  which  the  dis- 
charged sputum  was  not  carefully  and  at  once 
destroyed,  but  was  permitted  to  lodge  upon 
floors  or  clothing  or  articles  of  furniture,  where 
it  dried  and  finally  became  pulverized  and  car- 
ried as  dust  to  such  parts  of  the  room  as  are 
not  ordinarily  cleaned. 

Again,  some  one  will  say  :  "  If  it  be  true  that 
consumption  is  apt  to  be  acquired  by  breathing 
in  of  the  bacilli  with  the  dust,  then  we  ought 
to  find  in  the  lungs  of  persons  who  have  died 


DUST  AND  ITS  DANGERS.  67 

from  other  diseases  not  infrequently  the  com- 
mencements of  tuberculosis."  Now  this  is  in 
fact  just  what  we  do  find.  It  is  very  common, 
indeed,  to  find  in  those  little  filters  at  the  root 
of  the  lung, — the  lymph-glands  which  we  have 
spoken  of  in  another  chapter, — both  in  adults 
and  in  children  small  areas  of  tubercular  dis- 
ease, and  nothing  else  in  the  whole  body  indi- 
cating the  presence  of  the  germ.  The  disease 
here  has  not  been  extensive  enough  to  cause 
any  ill  effects  or  give  any  symptoms.  It  may 
be  in  an  early  stage  or  it  may  have  existed  for 
a  long  time,  or  it  may  have  altogether  healed, 
leaving  only  its  unmistakable  traces  behind 
(see  Fig.  6). 

But  more  than  this,  even,  we  have  learned 
about  the  early  stages  of  this  disease.  Many 
observers,  in  cases  of  accidental  death  in  ap- 
parently healthy  persons,  have  examined  these 
lymph  filters  (lymph-glands),  and  found  them 
in  appearance  perfectly  healthy,  and  yet  on 
applying  one  of  the  most  delicate  and  effective 
tests,  have  found  that  after  all  they  did,  in  a 
considerable  proportion  of  the  cases  exam- 
ined, contain  living  tubercle  bacilli.  These 


68  DUST  AND  ITS  DANGERS. 

were  present,  but  had  not  yet  set  up  even  a 
local  disease. 

It  has  been  shown,  by  a  careful  series  of  re- 
cent observations,  that  when  due  care  and 
intelligent  cleanliness  are  provided  for,  the  at- 
tendants upon  consumptives  in  hospitals  and 
in  private  houses,  are  not  subject,  in  any 
marked  degree  to  the  acquirement  of  the  dis- 
ease. But,  on  the  other  hand,  it  has  been 
equally  fully  proven  that  when  proper  cleanli- 
ness is  not  exercised,  and  the  expectoration  of 
the  patients  not  intelligently  cared  for,  the 
attendants  in  hospitals  for  consumptives  have 
with  notable  frequency  fallen  victims  to  the 
disease. 

More  proof  than  is  in  our  hands  is  hardly 
needed  that  in  a  very  large  proportion  of  cases 
in  inhabited  regions  the  infective  agent  or  germ 
of  tuberculosis  is  conveyed  from  sick  to  well  per- 
sons by  means  of  the  material  discharged  from 
the  lungs,  which  is  allowed,  from  carelessness 
or  ignorance,  to  dry  and  finally  mingle  with  the 
floating  dust. 

While  thus  tuberculous  persons  may  be  a 
constant  source  of  danger  to  their  healthy  fel- 


DUST  AND  ITS  DANGERS. 


lows,  it  is  by  no  means  true  that  they  always 
are  or  ever  need  to  be.      The  breath  itself,  the 


FIG.  6. — LYMPH  FILTERS  (LYMPH-GLANDS)  AT  THE  ROOT  OF  THE 
LUNG,  THE  SEAT  OF  LOCAL  AND  HEALED  TUBERCULOSIS. 

Two  of  the  lymph  filters  at  the  root  of  the  lung  which  have 
become  blackened  from  inhaled  dust.  But  in  addition  to  this,  one 
of  them — the  larger — shows  two  white  spots  which  are  caused  by 
the  lodgment  here  of  the  tubercle  bacilli.  These  germs,  caught  in 
the  meshes  of  the  filter  and  thus  kept  out  of  the  blood,  have  grown 
here  for  a  time.  But  owing  to  their  growth  or  their  presence,  the  tissues 
about  them  have  been  so  stimulated  or  irritated,  that  a  dense  organ- 
ized wall  has  been  formed  around  the  germs,  completely  shutting  them 
off  from  the  rest  of  the  body.  This  is  the  way  in  which  the  cure  of 
consumption  is  sometimes  effected.  Nowhere  else  in  the  body  of  this 
person,  who  died  from  an  acute  disease,  were  there  any  evidences 
whatsoever  of  tuberculosis, 


7O  DUST  AND  ITS  DANGERS. 

exhaled  air  of  consumptives,  no  matter  how 
seriously  ill,  is  not  dangerous ;  it  carries  no 
germs.  It  is  only  the  solid  discharged  mate- 
rial of  the  sputum  which  carries  the  danger. 
And  this  sputum,  moist  and  usually  adherent 
as  it  is  when  fresh,  is  only  dangerous,  so  far  as 
contamination  of  the  air  is  concerned,  when  it 
is  permitted  to  dry. 

Here  we  seem  to  be  at  the  root  of  the  evil. 
The  reason  why  consumption  is  so  widespread 
and  the  most  important  element  in  this  appall- 
ing mortality  is  simply  that  consumptive  per- 
sons, either  from  ignorance  or  carelessness,  are 
distributing  the  poison  not  only  everywhere 
they  go,  but  everywhere  the  dust  goes  which 
has  been  formed  in  part  by  the  undestroyed 
germ-laden  material  expelled  from  their  lungs. 
This  is  what  has  been  mistaken  for  so  many 
years  as  evidence  of  the  hereditary  transmis- 
sion of  consumption,  as  proof  that  consumption 
"  runs  in  families."  The  house-mates  have 
unwittingly  poisoned  one  another,  usually,  no 
doubt,  through  the  dust.  We  are  but  just  be- 
ginning to  recognize  this.  We  have,  indeed, 
known  what  caused  consumption  but  a  very 


DUST  AND  ITS  DANGERS. 


few  years,  and  even  many  intelligent  physi- 
cians are  not  yet  sufficiently  impressed  with 
the  inexpressible  importance  of  scrupulous 
cleanliness  in  tuberculosis  to  urge  it  as  they 
should. 

The  way,  then,  to  most  efficiently  stop  the 
prevalence  of  this  distinctly  preventable  dis- 
ease is  evidently  to  see  that  the  sputum  of 
consumptives  is  properly  disposed  of.  When 
this  is  practicable  it  should  be  received  in 
small  paper  cups,1  made  for  this  purpose,  and 
as  soon  as  possible  burned.  The  reception  of 
the  sputum  upon  fabrics  of  any  sort  is  always 
to  be  deprecated. 

The  reason  why  the  use  of  cloths  or  hand- 
kerchiefs for  the  reception  of  the  expectoration 
in  consumption  should  be  as  much  as  possible 
avoided  is  that  on  these  the  material  very 
readily  dries,  and,  becoming  detached  with  or 
without  the  minute  particles  of  fabric,  readily 
floats  off  in  an  inhalable  condition  into  the  air. 
For  the  same  reason,  great  care  should  be 
exercised  by  consumptives  to  avoid  the  soiling 
by  sputum  of  woollen  garments  from  which 

1  These  are  now  in  the  market  and  sold  cheap  by  druggists, 


72  DUST  AND  ITS  DANGERS. 

very  fine  fibre  particles  are  always  very 
readily  detached,  and  would  carry  with  them 
dried  particles  of  germ-laden  material,  should 
such  have  been  allowed  to  fall  upom  them. 

But  if  cloths  must  be  used,  as  will  often  be 
the  case,  either  to  receive  the  expectoration  or 
for  wiping  the  mouth,  they  should  be  such  as 
can  be  as  speedily  as  possible  burned  with 
their  contents.  When  handkerchiefs  are  used 
they  should  be  as  early  as  possible  boiled  for  a 
full  hour  in  a  receptacle  by  themselves  before 
they  are  washed  in  the  ordinary  way.  Cheap 
paper  cuspidores  are  now  made  which  should 
be  placed  in  all  apartments  frequented  by  con- 
sumptives, and  frequently  changed  and  with 
their  contents  burned. 

The  greatest  drawback  in  the  suggestion  of 
such  rules  of  procedure  as  would  be  efficient  in 
preventing  the  spread  of  tuberculosis  is  the 
certainty  that  they  will  not,  in  a  great  many 
cases,  be  followed.  Persons  who  are  cleanly 
enough  in  private  houses  will  spit  upon  the 
street,  or  in  public  conveyances,  or  on  the 
floor  of  theatres  and  other  places  of  assembly, 
and  until  the  knowledge  that  the  sputum  of 


DUST  AND  ITS  DANGERS.  73 

consumptive  persons  may  be  dangerous  shall 
have  become  widespread,  our  efforts  in  the  di- 
rection of  the  prevention  of  this  disease  will 
continue  to  be  counteracted  by  the  misdeeds 
of  the  ignorant  and  careless. 

Consumption  is  at  best,  if  it  has  any  best,  a 
most  distressing  and  deplorable  malady.  But 
when  we  have  learned,  as  we  have  within  the 
last  decade,  that  the  chances  of  recovery  are 
often  very  good  indeed  ;  that  it  is  not  hopeless, 
as  was  formerly  believed ;  that  it  is  not  in- 
herited ;  when  we  appreciate  that  with  due 
care  the  stricken  one  need  not  in  the  least  be 
a  source  of  danger  to  others,  even  to  his  house- 
mates ;  when  we  fully  realize  that  the  appalling 
prevalence  and  mortality  of  the  past  has  been 
due  to  ignorance  of  the  nature  of  the  disease 
and  the  mode  of  its  transmission,  we  should  be 
able  to  appreciate  how  much  we  owe  of  com- 
fort and  of  hope  to  the  investigations  in 
scientific  medicine,  which  have  given  us  all 
this,  if  they  have  not  yet  brought  to  us  such 
means  as  will  directly  cure  the  disease  in 
individuals  when  once  firmly  established. 


CHAPTER  IX. 

DUST-DANGERS     OUT-OF-DOORS    AND     IN     PRIVATE 

HOUSES,     WITH     SUGGESTIONS    FOR 

THEIR     AVOIDANCE. 

WITH  all  these  facts  about  the  most 
common  way  in  which  consumption  is 
transmitted  from  one  to  another  before  us,  we 
are  ready  to  consider  what  the  places  are  in 
which  healthy  persons  are  most  likely  to  be 
forced  to  breathe  air  which  contains  this  or 
other  infective  dust,  and  what  should  be  done 
to  avoid  it. 

It  should  always  be  held  in  mind,  in  con- 
sidering the  facts  and  suggestions  which  this 
chapter  contains,  that  the  safeguards  of  the 
body  against  inhaled  germs,  which  we  have 
already  looked  at  in  another  chapter,  are 
constantly  in  action,  and  in  large  degree,  in 
many  persons,  actually  and  wholly  protect 

74 


DUST  AND  ITS  DANGERS.  75 

against  danger,  even  in  very  dirty  and  very 
infectious  places.  Many  disease-producing  bac- 
teria die,  soon  after  they  are  expelled  from  the 
bodies  of  sick  persons  ;  many  are  swept  away 
by  the  winds  into  uninhabited  regions ;  many 
are  killed  by  sunlight ;  many  fail  to  come  in 
contact  under  favorable  conditions  with  sus- 
ceptible human  beings.  But  these  natural  safe- 
guards cannot  be  implicitly  relied  upon  for 
safety  by  any  one  at  all  times,  nor  can  any 
one  with  impunity  overtask  their  capacities 
by  unnecessary  and  constant  exposure  of  his 
person  to  infective  dust. 

It  is  certain  that  in  the  out-of-doors  air  in  the 
country,  and  also  in  cities  whose  streets  are 
kept  decently  clean,  there  is  little  danger  of 
harm  from  the  inhalation  of  germs  of  con- 
sumption or  of  any  other  disease,  because  the 
constant  purifying  agency  of  wind  and  air 
currents  will  either  soon  sweep  away  the  dust 
or  so  largely  dilute  it  that  it  will  be  practically 
free  from  disease  germs,  the  sources  of  which 
are  so  comparatively  limited.  If,  however,  the 
streets  of  cities  be  or  are  allowed  to  remain 
filthy,  so  that  abundant  and  pretty  constant 


76  DUST  AND  ITS  DANGERS. 

dust-clouds  are  encountered  by  those  passing 
through  them  ;  if  the  streets  are  not  properly 
sprinkled  before  sweeping,  either  by  machine 
or  hand  ;  if  ignorant  or  careless  street-cleaners 
are  allowed  to  scatter  clouds  of  dust  about 
them  as  they  sweep  or  shovel  or  transport  the 
pulverized  filth,  the  chances  of  inhalation  of 
dangerous  dust  particles  are  proportionally 
increased.  But,  on  the  whole,  the  risk  of 
infection  out-of-doors  from  dust,  even  in 
crowded  towns,  unless  they  are  notably  filthy, 
is  not  actually  very  great. 

Indoors,  however,  the  conditions  are  en- 
tirely different.  Let  us  first  consider  private 
houses  and  living  rooms.  Here,  as  we  have 
already  seen,  the  sources  of  micro-organisms 
are  various,  but  we  need  consider  here  only 
those  which  cause  consumption.  These  may 
be  brought  in  on  feet  and  garments  from  the 
streets  or  other  places,  or  be  blown  in  through 
open  windows  or  drawn  in  by  other  modes 
of  ventilation.  If  there  be  no  consumptive 
persons  in  the  house  or  rooms,  these  chance 
sources  of  infection  are  all  that  need  be  re- 
garded. If  there  be  consumptives  in  the 


DUST  AND  ITS  DANGERS.  77 

rooms,  no  further  danger  need  be  feared  if 
the  material  which  they  expectorate  or  dis- 
charge in  coughing  and  sneezing  be  carefully 
attended  to.  If,  on  the  other  hand,  consump- 
tives are  permitted  to  discharge  the  material 
raised  from  the  lungs  on  floors  or  elsewhere 
where  it  may  dry,  this  will  be  a  source  of  dan- 
ger far  exceeding  all  others.  In  houses  where 
healthy  persons  are,  then,  or  in  houses  where 
consumptives  are  who  are  intelligently  clean 
in  their  habits,  the  chances  of  inhaling  the 
tubercle  bacilli  are  slight.  But  it  should  al- 
ways be  remembered  that  these  chances, 
whether  small  or  great,  are  directly  dependent 
upon  the  means  which  are  used  to  get  rid 
of  the  dust.  If  this  be  permitted  to  accumu- 
late so  that  it  is  liable  to  be  stirred  up  over 
and  over  again  by  the  movements  of  persons 
in  the  room,  by  so  much  will  the  risks  be 
increased  of  inhaling  the  harmless  germs  of 
dust  and  with  them  sooner  or  later,  the  dan- 
gerous ones,  should  such  by  chance  be  present. 
It  is  perfectly  obvious  that  unless  the  win- 
dows be  widely  open  or  liberal  air  currents  in 
some  way  established,  the  too  common  method 


78  DUST  AND  ITS  DANGERS. 

of  so-called  "dusting" — that  is,  the  stirring  up 
of  the  dust  which  has  settled  on  the  smooth 
places  in  a  room  so  as  to  allow  it  to  settle 
again  on  to  the  rough  surfaces  or  inconspicu- 
ous places  where  it  does  not  show — is  worse 
than  useless,  since  the  dust  and  germs  are  not 
in  this  way  got  rid  of,  but  only  redistributed 
and  put  for  a  time  in  a  situation  suitable  for 
inhalation. 

Carpets  and  heavy  hangings  and  upholstery 
with  rough  goods  all  insure  the  more  or  less 
persistent  retention  of  dust  particles  in  rooms 
and  with  these  the  harmful  germs,  if  such  are 
present. 

Hard  floors,  with  rugs  which  may  be  cleaned 
out-of-doors,  as  few  and  as  light  hangings 
as  are  practicable,  furniture  upholstered  as  far 
as  may  be  with  smooth-surfaced  fabrics,  the 
use  of  moist  dusting-cloths,  and  the  wide  open- 
ing of  windows  and  doors  when  cleaning  is 
going  on, — these  are  the  general  suggestions, 
which,  if  followed,  will  confer  in  a  large  degree, 
even  in  populous  towns,  a  sense  of  security 
against  the  dangers  of  dust  in  private  houses 
in  which  healthy  persons  live. 

We   need   here   only  call   attention  in  the 


DUST  AND  ITS  DANGERS.  79 

briefest  way  to  many  devices  in  the  lore  of 
the  enlightened  housekeeper  for  cleaning  of 
carpeted  floors  without  raising  clouds  of  dust 
which  seem  more  objectionable  the  more  we 
know  about  them.  Such  practices  as  the  sprink- 
ling of  carpets  with  scraps  of  wet  newspaper, 
or  moist  tea-leaves,  or  other  substances  which 
keep  down  the  dust :  the  use  of  some  of  the 
more  perfect  forms  of  carpet-sweepers,  vacuum 
cleaners,  etc.,  may  be  considered  in  solving 
the  problem  of  clean  living  places  in  towns. 

The  writer  can  perhaps  imagine  the  fine 
scorn  with  which  his  meek  suggestions  in  this 
direction  may  be  met  by  the  experienced 
housekeeper,  and  indeed  makes  no  virtue  of 
insisting  upon  method  so  long  as  the  removal, 
and  not  the  simple  redistribution  of  the  dust, 
be  the  end  accomplished. 

In  houses  and  larger  buildings  which  are 
supplied  with  a  system  of  forced  ventilation,  or 
wherever  the  ventilation-draught  is  strong 
enough,  a  great  deal  may  be  accomplished  in 
the  way  of  keeping  the  dust  out  of  the  buildings 
by  the  use  of  cheese-cloth  or  thin  cotton  batting 
screens  placed  across  the  air  currents  near  the 
entrance  of  the  ventilation-shafts. 


CHAPTER   X. 

DUST-DANGERS  IN  PUBLIC   BUILDINGS   AND  PUBLIC 
CONVEYANCES. 

WE  come  now  to  another  class  of  places 
in  which  dust  is  a  matter  for  very  seri- 
ous consideration.  I  mean  theatres,  churches, 
schools,  and  court-rooms  and  other  places  of 
assembly  in-doors  where  large  numbers  of  per- 
sons are  frequently  crowded  together.  Here 
the  individual  in  the  matter  of  the  cleanliness 
of  the  air  he  breathes  is  largely  at  the  mercy 
of  his  fellows,  and  especially  of  the  persons 
too  often  ignorant  and  careless  to  whom  is 
intrusted  the  more  or  less  frequent  sweeping, 
dusting,  or  other  cleaning  of  the  rooms. 

So  prevalent  is  consumption,  and  so  insidi- 
ous in  its  onset  that  there  are  very  few  large 
assemblages  in  which  some  victims  of  the  dis- 
ease are  not  present.  Such  persons,  if  not 

80 


DUST  AND  ITS  DANGERS.  8 1 

informed  of  the  danger  of  the  practice,  will  be 
apt  to  convey  some  of  the  material  discharged 
from  the  lungs  to  situations  in  which  without 
care  and  vigilance  on  the  part  of  those  who 
afterwards  clean  the  rooms,  it  may  form  a  part 
of  inhalable  dust. 

Many  of  the  theatres  are  probably  the  most 
likely  places  of  any  which  we  know  frequented 
by  healthy  persons  in  large  cities  for  the  inha- 
lation of  disease  germs  of  one  kind  or  another, 
especially  the  germ  of  tuberculosis.  The  ven- 
tilation is  usually  wholly  inadequate  even  for 
the  purpose  of  carrying  off  the  vitiated  air  of 
respiration  or  exhalation,  and  is  of  almost  no 
use  in  freeing  the  air  of  dust.  Close  walled 
they  are  apt  to  be,  so  that  large  volumes  of 
out-door  air  rarely  or  never  sweep  through 
them  ;  sunlight  is  usually  excluded  ;  carpeted  ; 
the  chairs  upholstered  in  plush  ;  visited  by 
large  numbers  of  all  kinds  of  people,  who,  in 
the  long  sittings,  cleanse  their  shoes  on  the 
carpets,  if  they  do  not  add  to  this  their  sali- 
vary contributions.  The  floating  particles  ac- 
cumulate in  theatres  in  enormous  quantities, 
in  such  quantities,  indeed,  that  the  tell-tale  elec- 


Si  DUST  AMD  ITS  DAtfGE&S. 

trie  light  beams  show  a  blue  or  gray  cloud  on 
most  occasions  where  they  pierce  the  dust-la- 
den air.  Now,  it  is  a  fact  that  in  most  theatres 
at  least  there  is  no  efficient  means  made  use 
of  to  get  this  accumulating  dust  out  of  the 
auditorium.  The  coarser  dirt  is  swept  up 
more  or  less  frequently  in  all  of  them,  and 
carried  off,  but  the  finer  dust  is  usually  simply 
stirred  up  again  in  a  perfunctory  and  wholly 
useless  way  from  the  seats  to  settle  back  again 
into  the  plush  or  the  carpets,  to  be  stirred  up 
anew  by  the  incoming  and  outgoing  audience. 
The  fact  is,  the  upholstering  of  the  chairs  of 
public  assembly-rooms  ought  never  to  be  done 
with  plush  or  other  rough  fabric  which  catches 
and  holds  the  dust.  The  floors  should  not  be 
carpeted,  as  there  are  plenty  of  other  whole- 
some substitutes,  and  both  the  ventilation  and 
the  daily  cleansing  ought  to  be  done  under 
some  intelligent  direction,  so  that  these  places 
need  not  continue  to  be,  as  so  many  of  them 
now  are,  veritable  death-traps  and  distributing 
centres  of  bacterial  disease.  While  there  are, 
of  course,  exceptions  to  the  condition  of  affairs 
which  has  here  been  described,  the  exceptions 


DUST  AND  ITS  DANGERS.  83 

are  not  by  any  means  always  or  usually  the 
more  fashionable  or  popular  theatres. 

This  matter  of  enforcing  reasonable  cleanli- 
ness in  theatres  and  other  places  of  assembly 
rests,  as  all  other  matters  of  sanitary  reform 
ultimately  do,  with  the  people  themselves.  So 
long  as  the  patrons  of  filthy  theatres,  either 
fashionable  or  not,  permit  themselves  to  remain 
the  victims  of  ignorance  or  carelessness  or  cu- 
pidity the  managers  of  theatres  will  doubtless 
continue  to  do  just  what  they  have  been  doing 
and  are  doing,  no  matter  what  in  their  prac- 
tices is  shown  to  be  dangerous. 

Whoever  has  had  occasion  to  visit  the  court- 
rooms in  the  city  of  New  York — and  similar 
conditions  are  widely  prevalent  in  court-rooms 
as  well  as  legislative  halls  elsewhere  in  this 
land — cannot  fail  to  have  been  impressed  with 
the  general  filthiness  and  dustiness  and  stuffi- 
ness which  is  so  pronounced.  With  the  evils 
which  vitiated  air  causes  all  are  more  or  less 
familiar,  but  to  these  evils  even  the  large  intel- 
ligence of  the  members  of  the  legal  profession 
usually  supinely  submits.  That  poisoned  dust 
should  be  added  to  the  burden  simply  because 


84  DUST  AND  ITS  DANGERS. 

there  is  no  general  protest  against  the  careless- 
ness or  ignorance  which  is  displayed  in  the 
so-called  cleaning  of  these  places,  seems  almost 
incredible  when  the  importance  of  the  matter 
is  once  realized.  In  the  same  deplorable  con- 
dition are  many  of  the  public  school-rooms  in 
both  large  and  small  towns.  Ventilation  is 
slowly  becoming  recognized  as  important,  but 
the  removal  of  dust,  which  in  crowded  places 
is  very  liable  to  be  infectious,  is  not  systemati- 
cally attended  to. 

Public  conveyances  into  which,  especially  in 
this  country,  people  are  huddled  indiscrimi- 
nately, are  very  rarely  properly  cleaned  and 
dusted.  Of  course,  in  these  it  is  not  the  ordi- 
nary inorganic  dust,  the  fine  coal  or  iron  or 
sand  particles  which  are  most  to  be  dreaded, 
but  the  materials  which  come  from  uncleanly 
travellers  who  are  the  victims  of  bacterial  dis- 
ease. The  dangers  will  be  removed  only  when 
the  travellers  themselves  realize  that  the  dis- 
gusting and  very  prevalent  habit  of  spitting 
upon  the  floor  of  public  conveyances  is  not 
only  filthy  but  may  be  positively  dangerous, 
and  the  managers  of  the  transportation  com- 


DUST  AND  ITS  DANGERS.  85 

panics  see  to  it  that  their  conveyances  are 
actually  frequently  cleaned. 

A  railway-car  which  comes  in  from  its  hun- 
dred-mile trip  is,  when  vacated  by  its  occupants, 
usually  an  extremely  filthy  place  ;  dangerous 
even,  if  by  chance  it  has  borne  an  uncleanly 
passenger  afflicted  with  bacterial  disease.  And 
yet,  as  every  observant  person  who  travels 
much  has  often  seen,  these  cars  may  be  started 
out  on  the  return  with  their  full  loads  of  fresh 
victims,  after  no  other  cleaning  than  a  few 
random  broom-sweeps  and  a  few  flips  of  the 
feather-duster  over  the  window-seats  and  plush- 
covered  chairs — the  windows  usually  tightly 
closed  meanwhile,  and  the  doors,  possibly,  but 
by  no  means  always,  opened. 

But  here  again,  if  the  travelling  public  will 
not  protest  against  the  filthiness  of  many  pub- 
lic conveyances,  and  insist  upon  a  more  intel- 
ligent and  careful  system  of  cleaning,  matters 
will  probably  remain  as  they  are.  Where  com- 
petition exists  between  the  transporting  com- 
panies, persistent  public  protest  will  in  the  end 
be  heeded.  Where  competition  does  not  ex- 
ist, woe  to  the  traveller. 


86  DUST  AND  ITS  DANGERS. 

In  the  ill-cleansed  subways  of  New  York 
fine  iron  dust  from  the  break  shoes  is  added 
in  large  quantities  to  the  common  dust  of  the 
overcrowded  cars. 

Sleeping-cars  and  the  state-rooms  of  steam- 
ships and  hotel  bedrooms  are  almost  always 
liable  to  contain  infectious  material,  if  they 
have  been  recently  used  by  uncleanly  consump- 
tives or  those  ignorant  of  the  danger  of  their 
expectoration.  When  the  infectious  nature  of 
consumption  becomes  more  generally  appre- 
ciated, hotels  and  transportation  companies 
over  long  routes  will  be  compelled  to  provide 
special  accommodations  for  such  persons  as 
are  known  to  be  thus  afflicted.  In  the  mean- 
time, more  careful  attention  to  the  cleaning 
and  dusting  (that  is  actual  removal  of  dust) 
of  such  places  will  do  much  to  mitigate  the 
evil.  In  public  buildings  with  bare  floors  the 
use  of  properly-wetted  sawdust,  sprinkled  over 
the  floors  before  sweeping,  should  be  more 
generally  followed  than  it  is. 

While  the  transmission  of  the  tubercle  bacil- 
lus from  tuberculous  persons  to  others  through 
dust  is  of  serious  import,  the  risks  are  greatly 


DUST  AND  ITS  DANGERS.  8/ 

diminished  by  the  fact  that  in  drying,  and 
especially  in  sunlight,  a  large  number  of  the 
tubercle  bacilli  die  and  so  become  harmless. 

There  is  one  way,  however,  in  which  the 
tubercle  bacillus  is  frequently  transmitted  from 
one  person  to  another  in  full  vigor  and  viru- 
lence, which  is  of  such  great  importance  that 
we  must  consider  it  here,  though  it  does  not 
strictly  belong  in  a  discourse  upon  dust. 

In  sneezing  and  coughing,  particles  of  saliva 
or  bronchial  or  nasal  secretion,  or  material  from 
the  lungs  of  those  who  are  the  victims  of  pul- 
monary tuberculosis  and  may  contain  bacilli, 
are  thrown  out  in  the  form  of  a  fine  spray. 
This  is  particularly  the  case  in  sneezing.  This 
fine  spray  may  float  in  the  air  for  a  consider- 
able time  and  can  be  breathed  in  by  persons 
several  feet  from  a  vigorous  sneezer. 

There  is  abundant  evidence  that  in  this  way 
intimate  association  with  tuberculous  persons 
may  lead  to  infection.  The  prevention  of  this 
evil  lies  in  holding  the  handkerchief  over  the 
nose  and  mouth  in  coughing  and  sneezing. 
This  counsel  of  decency  is  worthy  of  conside- 
ration at  all  times  where  persons  are  closely 


88  DUST  AND  ITS  DANGERS. 

associated.  For  in  this  way  the  infective 
agents  of  pneumonia,  diphtheria,  influenza, 
and  of  many  common  colds  are  also  widely 
disseminated. 


CHAPTER  XI. 

SOME     OBJECTIONS,    PROTESTS,    AND     QUERIES 
ANSWERED. 

MANY  usually  very  reasonable  persons, 
when  brought  face  to  face  with  such 
disagreeable  facts  as  have  been  here  set  forth, 
are  disposed  to  petulantly  exclaim  that  they 
and  their  friends  have  got  along  very  well  thus 
far  with  the  dust  which  they  have  encountered, 
and  that  they  don't  want  to  be  worried  with 
the  possibilities  of  danger  which  may  lurk  un- 
seen about  them.  The  world's  people,  they 
say,  have  managed  to  live  along  in  large  num- 
bers for  a  good  many  centuries  without  know- 
ing any  thing  about  the  bacteria  which  may  be 
sporting  in  this  excellent  canopy,  the  air. 

To  these  rather  short-sighted  and  impatient 
expostulations  it  may  be  answered  :  The  fact 
still  remains  that  about  one  out  of  seven  of 

89 


9°  DUST  AND  ITS  DANGERS. 

all  the  people  who  die  are  prematurely  carried 
off  by  tuberculosis,  and  a  large  proportion 
of  these  through  dust-poisoning,  which  if  we 
choose  we  can  largely  prevent.  We  are  apt 
to  forget  that,  as  soon  as  we  know  the  cause 
and  the  means  of  prevention  of  a  disease  like 
consumption,  the  responsibility  for  a  large 
death-rate  is  no  longer  to  be  laid  to  the  charge 
of  Providence  or  fate,  but  at  the  door  of  human 
ignorance  or  carelessness.  We  are  apt  to  for- 
get, too,  that  such  dangers  from  uncleanly  air 
are  constantly  increasing  with  the  crowding 
together  of  large  numbers  of  people  in  cities, 
and  especially  in  cities  in  which  the  manage- 
ment of  municipal  affairs  is  in  the  hands,  not 
of  intelligent  and  honest  men,  but  of  political 
tricksters  and  unjailed  thieves. 

We  pay  the  penalty  of  the  close  huddling  to- 
gether of  large  numbers  of  people  in  cities,  by 
the  increasing  vigilance  which  we  must  exer- 
cise to  prevent  the  spread  of  infectious  disease. 
We  may  deplore  the  necessity  for  such  homely 
and  incessant  painstaking  as  is  imperative  if 
we  would  keep  our  living-places  clean  and 
wholesome  ;  we  may  carp  and  cavil  at  sanitary 


DUST  AND  ITS  DANGERS.  9 1 

preachments  if  we  will,  but  we  ignore  them  at 
our  peril.  Rich  or  poor,  high  or  low,  ignorant 
or  learned,  all  are  alike  liable  to  become  the 
victims  of  such  diseases  as  are  spread  in  the 
floating  dust  of  ill-kept  towns  and  dust-ridden 
houses. 

If  the  prevention  of  the  spread  of  consump- 
tion were  a  matter  which  could  be  carried  out 
by  physicians  alone  there  would  indeed  be 
little  use  in  inciting  a  general  apprehension  of 
the  dangers  of  dust-poisoning.  But,  unfortu- 
nately, this  is  not  possible.  If  we  are,  in  any 
large  degree,  to  limit  the  ravages  of  consump- 
tion, and  with  it  the  evils  of  many  other  bacterial 
diseases,  this  must  be  done  through  the  thor- 
ough understanding  of  the  danger  and  its 
nature  by  the  people  at  large,  and  the  practice 
of  proper  cleanliness  in  the  houses  which 
they  directly  control,  and  also  by  forcing  clean- 
liness upon  the  managers  of  public  places, 
which  in  the  end  they  also  ultimately  control 
through  public  opinion. 

If  it  be  not  worth  while  to  save  one  out  of 
every  eight  or  ten  or  one  hundred  or  one  thou- 
sand from  the  distress  and  pain  and  misery  of 


92  DUST  AND  ITS  DANGERS. 

the  consumptive's  lot,  then  such  considerations 
as  have  been  urged  in  this  book  are  worse  than 
useless.  But  if,  on  the  other  hand,  the  moder- 
ate care  and  attention  to  cleanliness  in  the  places 
in  which  we  live  or  which  we  frequent  is  but  a 
small  price  to  pay  for  the  large  immunity  from 
disease  which  would  surely  follow,  then  the  end 
in  view  would  seem  fully  to  justify  any  pains 
which  we  may  take  to  make  and  keep  our 
living-places  clean  and  wholesome. 

Many  are  disposed  to  assume  that  in  towns 
whose  affairs  are  administered  by  dishonest  or 
careless  officials  the  task  of  cleanliness  in 
houses  is  a  nearly  hopeless  one,  and  this,  in  a 
measure,  is  true.  But  we  are  too  prone,  in 
this  country,  to  permit  ourselves  to  be  imposed 
upon  in  countless  ways  without  protest,  and 
with  a  supineness  or  indifference  which  is  little 
short  of  disgraceful. 

There  is  probably  no  city  or  town  in  the 
United  States  which  need  be  either  misgov- 
erned or  filthy,  if  only  the  respectable  people 
would  intelligently  unite  in  the  assertion  of 
their  rights.  In  the  matter  of  dust  and  street 
dirt,  in  which  regard  the  city  of  New  York  is 


DUST  AND  ITS  DANGERS.  93 

ever  in  such  a  desperate  case,  more  is  in- 
volved than  individual  right  or  personal  com- 
fort. We  virtually  condone  manslaughter  just 
as  long  as  we  permit  men  to  hold  municipal 
offices  who  fail  in  their  plain  duty  in  the 
protection  of  the  public  health.  From  mayor 
to  scavenger  they  should  be  held  personally 
responsible,  and  no  political  chicanery  per- 
mitted to  obscure  or  call  away  public  attention 
from  the  business  which  such  persons  are 
appointed  and  paid  to  attend  to.  We  owe  a 
great  deal  to  the  vigilance  of  the  press  in 
calling  attention  to  sanitary  abuses,  but  with- 
out the  steady  and  persistent  urgency  of 
individual  protest  this  is  of  but  little  avail. 

Until  the  recent  revelations  in  bacteriology 
gave  us  firm  ground  to  stand  upon  in  forming 
our  conceptions  of  the  cause  of  contagious  and 
infectious  diseases,  there  was  something  most 
mysterious  and  dreadful,  and  the  more  uncanny 
because  mysterious,  about  the  agency  which 
could  so  subtly  convey  a  dreaded  disease  from 
one  to  another.  That  invisible  thing  which 
could  linger  about  a  room  or  cling  to  a  folded 


94  DUST  AND  ITS  DANGERS. 

garment  for  weeks  or  months — which  could 
pass  unseen  through  the  air  and  work  desola- 
tion far  away — was  something  which  might 
well  inspire  awe,  if  not  superstition. 

To-day,  however,  the  whole  aspect  of  affairs 
has  changed.  We  have  at  last  found  out  that 
these  subtle  agencies  in  the  diseases  of  this 
class  which  have  been  most  fully  studied,  are 
well-defined  organisms  which  we  can  isolate 
and  cultivate  and  study,  small  as  they  are,  with 
as  much  precision  and  certainty  as  we  can 
cabbages  and  pumpkins.  We  know  a  great 
deal  about  the  conditions  which  favor  their 
growth,  and  various  things  which,  at  least 
outside  of  the  body,  will  kill  them  and  render 
them  harmless. 

With  this  definite  knowledge  about  some  of 
the  agents  (bacteria)  which  cause  disease,  the 
most  impenetrable  of  the  mysteries  clustering 
about  the  infectious  diseases  have  passed  away. 
For  while  we  do  not  yet  know,  as  we  have  seen 
in  another  chapter,  the  exact  form  or  species 
which  is  concerned  in  causing  all  of  the  dis- 
eases of  this  class,  we  have  indisputable 
ground  for  assuming  that  they  all  are  caused 


DUST  AND  ITS  DANGERS.  9$ 

by  some  formed,  minute,  living"  thing,  either 
plant  or  animal.  This  leads  us  to  the  further 
definite  conclusion  that  whenever  one  of  the 
contagious  or  infectious  diseases  is  conveyed 
from  one  person  to  another,  this  is  done  by 
formed  material  which  must  pass  from  one  to 
another,  either  in  the  shape  of  palpable  solid 
matter  or  by  fine  floating  dust-particles. 

Now,  when  we  interpret  this  rather  long 
exposition  of  facts  and  inferences  into  every- 
day experience,  we  find  that  it  means  some- 
thing like  this  :  When  we  have  in  the  house 
a  victim  of  one  of  the  infectious  diseases,  such 
as  diphtheria  or  consumption,  and  want  to 
protect  the  house-mates  against  it,  both  while 
it  is  active  and  after  it  is  over,  we  no  longer 
grope  after  some  mysterous,  intangible  thing, 
before  which  we  must  bow  down  or  burn 
something,  as  if  it  were  some  demon  which  we 
would  exorcise.  We  say  to  ourselves,  if  we 
can  at  once  destroy,  by  boiling  it  or  burning  it 
or  soaking  it  in  some  suitable  disinfectant,  ail 
the  material  which  is  discharged  from  the 
patient's  body,  he  will  cease  to  be  a  source 
of  infection — the  poison  cannot  spread  from 


96  DUST  AND  ITS  DANGERS. 

him.  When  the  illness  is  over  and  we  disin- 
fect the  rooms,  we  aim  not  to  drive  out  any 
malign  spirit,  any  mysterious  kobold  lingering 
in  the  air,  but  we  are  trying  to  kill  the  bacteria 
or  other  similar  organisms  which  may  have 
escaped  our  vigilance  during  the  disease,  and 
in  more  or  less  solid  form  or  as  floating  dust 
have  found  lodgment  on  bedding,  furniture, 
garments,  or  on  walls  or  hangings.  In  all  the 
management  of  the  sick  room,  in  all  we  do  for 
the  person  of  one  suffering  from  an  infectious 
disease,  this  is  the  conception  which  we  should 
cherish  as  to  the  source  of  danger. 

Many  will  say,  in  view  of  what  has  been 
set  forth  in  this  little  book  about  the  trans- 
mission of  the  germ  of  consumption  by  floating 
dust :  "  Why  do  we  not  all  get  consumption, 
if,  as  he  says,  it  is  communicable  ?  We  should 
be  very  apt  to  catch  small-pox  or  scarlatina 
if  brought  in  contact  with  them.  It  can't  be 
true  that  consumption  is  communicable."  To 
this  it  may  be  answered  that  some  of  these 
diseases  are  much  more  readily  communicated 
than  others  are  from  person  to  person.  Thus 
scarlet-fever  and  measles  and  small-pox  are 


DUST  AND  ITS  DANGERS.  97 

much  more  readily  transmitted  than  is  diph- 
theria or  consumption  ;  they  are,  as  we  say, 
more  highly  contagious,  and  although  we  do 
not  yet  exactly  know  what  form  of  germ  causes 
scarlet-fever  and  measles  and  small-pox,  we  are 
pretty  certain  that  they  are  caused  by  germs 
or  lowly  organisms  of  some  kind,  and  that 
these  are  much  more  readily  or  freely  given 
off  from  the  body  than  are  the  germs  which 
cause  less  easily  communicated  diseases,  such 
as  consumption  and  diphtheria,  and  are  more 
liable  to  exist  in  the  form  of  particles  which 
float  in  the  air  as  impalpable  dust. 

Then,  again,  we  should  not  lose  sight  of  the 
fact  that  the  germ  of  consumption  is  a  slowly, 
growing  germ ;  that  it  is  killed  by  sunlight ; 
that  only  under  a  limited  range  of  conditions 
does  it  grow  at  all ;  and  that,  after  all,  the 
chances  are  not  very  great  for  each  one  of  us 
that  from  aerial  contaminations  a  sufficient 
number  of  the  living  bacilli,  even  if  breathed 
in  and  passing  all  the  safeguards  of  the  body 
against  such  intruders  at  last  find  lodgment  in 
the  tissues,  will  find  the  conditions  favorable  for 
inducing  the  disease.  Now  and  again  only  does 


98  DUST  AND  ITS  DANGERS. 

the  favorable  combination  of  conditions  occur, 
but — and  let  this  be  noted  well — the  nows  and 
agains  are  frequent  enough  in  the  aggregate  to 
secure  for  consumption  the  distinction  of  being 
the  most  common  and  serious,  as  it  is  the  most 
distinctly  preventable,  disease  known  to  man. 

It  might  be  thought  that  if  we  know  what 
form  of  germ  causes  a  given  infectious  disease, 
and  what  chemical  substance  or  drug  will  kill 
it,  we  could  readily  control  the  disease  when 
once  established  in  the  body  by  giving  a  medi- 
cine which  would  kill  the  germs.  So  we  could ; 
but  unfortunately  the  whole  body  is  made 
up  of  little  masses  of  living  matter,  which 
we  call  cells,  and  these  are  about  as  readily 
killed  as  bacteria  are  by  the  drugs  which  we 
should  like  to  use  for  this  purpose.  So  that  in 
killing  the  germs  we  should  be  apt  to  stop  the 
disease  indeed,  but  kill  the  body  too. 

We  hope  sometime,  as  has  been  already 
said,  to  find  some  sort  of  agency  which  will 
kill,  or  render  harmless,  the  germs  which  cause 
infectious  diseases  without  harming  the  body. 
But  in  the  meanwhile,  and  perhaps  always — 
since  the  Irishman's  conduct  in  swallowing 


DUST  AND  ITS  DANGERS.  99 

a  potato-bug  and  then  swallowing  Paris  green 
to  kill  it  was  not  very  rational — we  must  do 
the  best  we  can  along  the  lines  which  have 
been  suggested  in  this  book  to  prevent  the 
occurrence  of  these  diseases  by  destroying  the 
germs  before  they  get  scattered  in  the  dust,  or, 
failing  in  the  opportunity  for  this,  see  to  it 
that  the  dust  itself  is  intelligently  disposed  of. 
One  of  the  most  serious  obstacles  in  the  way 
of  clean  living  in  towns  in  this  country  is  the 
especially  American  expectoratory  prerogative, 
which  so  frequently  both  anticipates  and  ac- 
companies the  franchise  in  otherwise  decent 
males.  The  trick  is  early  acquired  by  our 
mongrel  immigrants,  who  lose  no  time  in  bet- 
tering our  instructions.  Could  women,  walking 
upon  our  streets,  leaving  cars,  and  descending 
from  elevated  railroad  stations,  but  see  them- 
selves and  their  environment  as  others  see 
them,  the  management  of  the  skirts  of  walk- 
ing-suits would,  it  would  seem,  command  from 
them  a  more  careful  attention.  We  must 
speak  plainly  here,  for  very  surely  unto  dust 
does  all  this  expectorated  unspeakableness 
soon  return. 

7 


IOO  DUST  AND  ITS  DANGERS. 

The  spectacle  of  the  well-dressed,  filthy 
brutes,  whom  natural  selection  has  most  un- 
kindly left  but  a  few  degrees  higher  than  their 
congeners  in  the  sty,  wallowing  in  their  ex- 
pectoration, about  certain  hotels  and  theatre 
entrances,  may  well  impress  the  sensitive  on- 
looker with  the  colossal  task  which  Nature 
undertook  when  she  set  to  work  to  evolve 
man,  and  the  lamentable  failures  which  are  so 
often  but  half-concealed  in  fashionable  attire. 


CHAPTER  XII. 

SUMMARY    AND   CONCLUSION. 

IF,  now,  we  sum  up  the  main  points  which 
have  been  urged  regarding  the  ordinary 
mode  of  transmission  from  one  to  another 
through  the  air  of  the  germ  of  consumption 
and  the  means  of  avoiding  it,  we  see,  in  the 
first  place,  that  the  most  complete  remedy  of 
existing  evils  is  simply  the  immediate  destruc- 
tion of  the  material  discharged  from  the  lungs 
of  affected  persons ;  second,  the  practice,  both 
in  private  houses,  in  places  of  assembly,  and 
in  public  conveyances,  of  more  intelligent  and 
efficient  systems  of  cleaning,  and  particularly 
the  adoption  of  appropriate  means  for  getting 
rid  of  the  floating  or  settled  dust. 

The  dust  of  ordinarily  clean  public  rooms 
and  of  private  houses  is  not,  as  we  have  seen, 
dangerous  or  especially  harmful  unless  it  has 

101 


102  DUST  AND  ITS  DANGERS. 


among  its  ingredients  the  living  germs  which 
have  come  from  the  bodies  of  persons  suffering 
from  bacterial  disease.  This  dangerous  ad- 
mixture in  dust  is  always  possible  in  populous 
towns,  and  while  the  danger  from  this  source 
is  in  general  not  very  imminent,  it  is  increased 
in  direct  proportion  to  the  accumulation  of  dust 
which  is  allowed  to  occur  either  in  private 
houses  or  places  of  assembly. 

Two  important  means  exist  for  getting  rid 
of  dust  either  in  private  houses  or  in  places  of 
assembly  or  public  conveyances.  The  first  is 
to  sweep  and  to  stir  up  the  dust  with  windows 
and  doors  wide  open,  so  that  the  temporarily 
floating  particles  may  be  largely  carried  out-of- 
doors,  where  they  will  be  soon  diluted  and  swept 
off.  It  should,  in  the  second  place,  be  borne 
in  mind  that  in  still  rooms  the  dust,  and  with 
it  the  larger  part  of  the  aerial  germs,  will 
settle,  within  a  few  hours,  so  as  to  leave  the 
room  almost  entirely  free  from  them.  If,  now, 
the  mopping  of  the  floor  or  the  dusting  of  furni- 
ture with  moist  cloths  be  practised,  the  larger 
part  of  the  dust  may  be  completely  removed 
from  the  rooms.  The  completeness  of  this 


DUST  AND  ITS  DANGERS.  1 03 

removal  will,  of  course,  depend  largely  upon 
the  simplicity  of  the  furnishing  and  the  intelli- 
gence which  is  used  in  the  work.  The  relega- 
tion of  the  work  of  sweeping  and  dusting  of 
rooms  to  ignorant  and  careless  servants,  with- 
out intelligent  and  persistent  supervision,  can- 
not be  expected  to  result  in  clean  living-places. 
We  realize  more  fully  now  than  ever  before, 
weighing  the  accumulated  experience  of  years 
in  the  light  of  the  new  knowledge  about  the 
cause  of  consumption,  that  this  disease  is  by 
no  means  always  a  hopeless  or  fatal  one. 
Many  persons  get  well,  and  many  more  so  far 
recover  as  to  enjoy  years  of  comfortable  life. 
We  do  not  yet  know  any  particular  drug  or  any 
especial  medical  treatment  which  can  be  depen- 
ded upon  to  cure  consumption.  But  we  do  know 
that,  by  putting  the  body  under  certain  favor- 
able conditions — proper  food,  suitable  climate, 
appropriate  regimen,  and  aiding  these,  when 
occasion  requires,  by  drugs, — the  physician  can 
often  hold  out  to  his  patient  this  well-grounded 
hope,  that  the  body's  natural  safeguards  against 
the  invasions  of  bacteria  reinforced  in  this  way 
may  lead  him  to  recovery  and  a  new  life.  But 


IO4  DUST  AND  ITS  DANGERS. 

this  lesson,  first  of  all,  the  patient  should  learn, 
that  he  must  see  to  it  that  all  expectoration  be 
destroyed,  or  else  he  is  constantly  running  the 
risk  of  reinfecting  himself,  and  thus  destroying 
his  chances  of  a  victory  over  the  disease,  and 
is,  moreover,  exposing  others  to  a  serious  risk 
of  acquiring  it. 

The  establishment  of  special  sanitariums  in 
the  country  where  consumptives  may  be  intel- 
ligently cared  for  is  not  only  of  great  benefit 
to  the  stricken  individuals  themselves — giving 
them,  as  a  rule,  the  best  chances  for  recovery, 
— but  is  of  incalculable  importance  to  commu- 
nities at  large,  since  it  removes  an  important 
and,  as  we  have  seen,  often  active  source  of 
dissemination  of  the  disease. 

It  has  not  seemed  to  fall  within  the  scope  of 
this  little  book  to  give  detailed  directions  as  to 
the  most  efficient  means  of  destroying  infec- 
tious material  in  the  sick  room  nor  the  modes 
of  disinfection  of  such  rooms  when  the  disease 
has  passed,  because  these  are  matters  which  will 
always  be  attended  to  by  the  physician  if  he  be 
intelligent  and  well  informed,  and  must  vary 
more  or  less  with  the  conditions  of  each  case. 


DUST  AND  ITS  DANGERS.  105 

A  little  thoughtful  consideration  of  the  facts 
and  principles  which  have  been  set  forth  can- 
not fail  to  result,  under  ordinary  circumstances, 
in  an  improved  sanitary  condition  of  the  places 
in  which  we  so  largely  spend  our  lives. 

We  are  just  entering  upon  a  new  epoch  in 
our  knowledge  of  disease.  The  discovery  of 
the  bacterial  origin  of  so  many  of  the  infectious 
diseases,  which  have  hitherto  been  as  myste- 
rious as  they  were  fatal,  has  placed  us  on  a 
higher  plane,  so  that  there  is  a  good  hope  that 
in  the  not  distant  future  we  may  not  only  in 
large  degree  limit  the  spread  of  these  diseases, 
but  even  learn  some  reliable  means  of  cure  for 
them.  We  have  in  our  hands  to-day  as  we 
have  seen  the  means  of  prevention  in  large 
measure  of  consumption  provided  the  simplest 
dictates  of  cleanliness  be  followed  and  the  same 
may  be  said  of  typhoid-fever,  diphtheria,  ery- 
sipelas, blood-poisoning,  and  several  other  in- 
fectious diseases. 

It  is  because  medical  science  is  raising  itself, 
in  the  light  of  our  new  knowledge,  to  the  higher 
plane  of  the  general  prevention  of  the  infec- 
tious diseases,  that  we  are  hearing  so  much 


106  DUST  AND  ITS  DANGERS. 

nowadays  about  bacteria  and  germs  and  infec- 
tion and  the  need  of  a  more  intelligent 
cleanliness. 

It  is  not  a  mere  fashion  at  whose  dictates 
the  doctrine  of  cleanliness  in  person,  food,  and 
air  is  being  so  widely  and  earnestly  proclaimed 
to-day.  It  is  no  fad  of  the  hour  which  is  to  pass 
and  be  forgotten.  If  our  research  into  the 
sources  of  widespread  human  ill  does  carry  us 
down  into  the  realm  of  the  invisible  world  we 
bring  from  it  such  knowledge  as  is  full  of 
significance  and  rich  in  the  promise  of  human 
weal,  if  we  do  but  heed  the  lessons  which  are 
already  clear,  precise,  and  not  easily  to  be 
mistaken. 


INDEX. 


Air,  amount  of,  used  for  biological  analysis        .....        23 

"  analysis,  biological,  methods  of                      .            .            .            .            .  13,  19 

"  "                 "           filtration  method  of                   .            .            .            .15 

41  "                 "           plate  method  of             .....  15-18 

"  bacteria  of,  as  disease  producers        .           .           .           .           .           .  52,  53 

"  contaminated  by  tubercle  bacilli  in  dust  of  .            .            .            .            .66 

41  effects  of  stirring  of,  in  altering  germ  contents        .            .            .            .31 

"  "        44  sweeping  on             .......  31-33 

41  exhaled,  freedom  of,  from  dust  and  germs   ......        69 

vl  filtration  of,  in  ventilating  shafts      .            .            .            .            .            •        79 

14  in-doors,  bacteria  in                  .            .           .            .            .            .            -33 

14  *4        dangers  of,  from  floating  dust            .            .            .            .            .76 

44  "        germs  in            »           .           .           .           .           .           •           .27 

14  '4        origin  of  germs  found  in                     .            .            .            .            «        3° 

14  u        spontaneous  freeing  of,  from  dust  and  germs         .            .            .37 

44  "        varying  number  of  germs  in  .            .            .            .            .            •        34 

"  modes  of  spontaneous  freeing  of,  from  dust  and  germs       .            .            .31 

44  of  theatres  and  other  public  places  as  sources  of  disease                                     81 

44  out-doors,  varying  number  of  germs  in         .            .            .            .            .  22,  23 

44  "           spontaneous  freeing  of,  from  germs       .            .            .            .21 

41  probability  that  consumption  is  commonly  transmitted  through              .        65 

11  street-,  in  cities,  dangers  of,  from  its  floating  dust             .            .            .75 

44  4l        in  New  York  during  cleaning             .            .            .            .            .  25, 26 

Antaeus  .....                                                                     l6 

Asiatic  cholera         .........        55 

Bacilli ...        13 

44     -tubercle 4« 

44  4i        dangers  from,  in  sputum  of  consumptives       .  .  .61 

M        habitat  of &4 

•l  "        in  bodies  of  apparently  healthy  persons  .  .  .67 

•*  **         "  dust  of  rooms  used  by  consumptives  .  .66 

107 


IO8  INDEX. 


PACK 

Bacilli-tubercle,  mode  of  action  of,  in  producing  consumption  .  .        60 

Bacillus  of  tuberculosis        ••••••..59 

Bacteria,  colonies  of  ,  .  ,  .  .  »  .  .        12 

definite  knowledge  of,  as  explaining  many  mysteries  of  disease      .        94 
disease-producing  .  .  .  .  .  .  •        53 

forms  of.  .  .  ,  .  .  .  .  .          y 

in  air  as  disease  producers          ......        52 

41  in-doors  dust    .  »  •  •.  .  .  •         "'^~^f 

"  out-doors  dust  .*•«....        21 

mode  of  determining  number  of,  in  air  .  .  .  .13 

modes  of  disposal  of,  in  the  body  when  inhaled         .  .46 

"  formation  of  dust  from  .  .  .  •  .         • 

modes  of  study  of  .  .  »  .  .  .  .11 

nature  of  .  .  .  .  .  .  .  .  .7 

occurrence  of,  in  nature  .  .  .  .  .  *         § 

relations  of,  to  infectious  diseases         .  .  .  •  •        55 

significance  of,  in  air  in  general  .  .  .  .  .        *o 

Bacterial-diseases,  remedial  agents  in       .  .  .  .  .  .98 

Berlin,  air  analyses  in          ........23 

Biological  air  analysis          ........19 

Blood-poisoning        ..••••••••55 

Boston,  air  analysis  in         .  ,  ,  .  .  .  .  .23 

Burning,  best  mode  of  destroying  germ-laden  sputum  in  consumption  .        72 

Carnelly ,  air  analyses  by    .            .            .            •            .  ,  .  .  23, 33 

Catarrh,  relations  of  dust  to            .            «           •           «  •  .  .52 

Cells,  ciliated,  in  air  tubes              .            .           «           *  .  »  .        38 

Central  Park,  N.Y.,  analysis  of  air  in      .            .           ,  *  «  ,       .25,26 

Cleaning  of  rooms    .            .            .            •            .            .  »  .  82,  86,  loa 

Cleanliness,  importance  of,  in  living  places        .            .  .  .  .92 

Cloths,  dangers  of  use  of,  to  receive  tubercular   sputum  .  .  .71 

Coldf .  .  .  •  56,  88 

College  of  Physicians  and  Surgeons,  N.  Y.,  air  analysis  at    .  .  .  33.  34 
Communicable  diseases       «••••«••        54 

Consumption              .            .           •           •           ••  •  •  .56 

"           a  preventable  disease           .           ,           .  •  •  .        57 

"            heredity  of     .            .            .                        •  •  •  •        59 

"            insidiousness  and  slow  beginning  of         .  •  •  57 

mode  of  transmission  most  common     N    •  .    •  *  •        64 

"            mortality  from           .            .            .            .  .  .  61,  62,  63 

most  direct  means  of  preventing  spread  of  •  .        71 

'*           pot  always  a  hopeless  disease        ,           ,  t  .  73«  I03 


INDEX.  109 


PAGE 

Consumption  not  one  of  the  highly  contagious  diseases  .  .  .96 

44  of  the  lungs  the  most  common  form  of  tuberculosis       .  .         65 

predisposition  of  certain  persons  to  ....        59 

prevalence  and  mortality  of  .  .  .  .  .  57, 61 

44  proper  food  and  surroundings  more  important  tha»  drugs  in 

the  treatment  of  ......       103 

spread  by  meat  and  milk     ......        64 

44  summary  of  the  reasons  of  prevalence  of  ...        70 

"  transmission    of,    in    unclean  sleeping-cars,   bedrooms,    and 

steamships  .......        86 

44  transmission  of,  to  attendants  upon  the  sick       .  .  .68 

44  tubercle  bacilli  the  only  direct  cause  of  .  .  .  -59 

"  ways  in  which  it  is  spread  by  dust  .  .  .  .58 

Contagion       ..........        95 

Contagiousness,  degrees  of,  in  bacterial  diseases  .  .  .  .96 

Cornet,  discovery  of  tubercle  bacilli  in  consumptives'  rooms    .  .  .66 

Cotton  niters  for  bacterial  air  analysis       ......         14 

Coughing,  infective  spray  in  .  .  .  .  .  77,  87 

Court-rooms,  filthy  and  dangerous  air  of  .  .  .  .  83 

Culture  medium  and  methods  for  germs  ......  11-14 

Destruction  of  discharged  material   best  means   for  preventing  spread  of 

bacterial  diseases             ......  101 

Diphtheria    .  .........  55-88 

Disease,  preventable             .            ».           •            .            .            .            •  54 

44        relation  of  dust  to  .•«..•••  5° 

Diseases,  infectious  .........  55 

44               "          presence  of  bacteria  in  explaining  many  mysteries  of       .  93 

44               "          relation  of  bacteria  to             .            .            .            .  55 

44        of  occupation         .           .           .           •           •           •           «  5 

Disinfection,  modern  notions  of,  more  precise                                        ;            .  95 

Drugs  in  infectious  diseases            .......  98 

Drying,  tubercle  bacilli  killed  by  .  .  .  .  •  •  .87 

Dundee,  air  analysis  in        ....                        .            .            «  23 

Dust,  as  means  of  spreading  consumption  or  tuberculosis          .  58 
41      "  source  of  danger  in  public  assembly  rooms      .            .            .            .81 

44      coal-  and  cotton-        ...•••••  + 

44      dangers  of,  in  public  buildings        ...«••  &° 

44      -dangers  out-doors  and  in-doors      ...•••  74 
44      definition  of    ..••••••• 

44      filtration  of,  out  of  lymph  in  the  lungs      .            .            .            •            •  45 

44      jn-doors,  germs  in      .            »           t            »            »            •           »           •  a? 


110  INDEX. 


PAGE 

Dust,  harmful  effects  of,  on  the  eyes       ••"•"•  •  •  .52 

44      in  inhaled  air,  disposal  of,  by  body  ,  ,     ,      ,  .          ','       §y 

"      "  public  conveyances    .       .,  ,  .  •  .  .  .84 

44      "  theatres,  or  as  means  of  conveyance  of  disease  ,  .  .81 

44      u  railway  carriages  as  source  of  danger     .  »  »  .  .        85 

44     in-doors,  danger  of  infection  from  .  .  •   -        ,  .  .76 

inorganic  elements  of  .  .  .  .  .  .  .4 

41  as  causes  of  disease  .  .  .  . '-  -  y 

lodgment  of,  in  tissues  of  lungs       ......        44 

materials  composing  .  .  «  .  .  .  .  .3 

'      metallic  .  .  .  .  .  .  .  .  .4 

mode  of  occurrence  of  bacteria  in   .  .  .  .  .  .8 

nature  of,  in  general ........          i 

1      organic  or  living  elements  of  ......         f 

'      out-of-doors,  micro-organisms  in    .  .  .  .  .  .        ao 

44      relations  of,  to  catarrh  .  .  .  .  .  .  .52 

"      removal  of,  from  houses        .......        77 

"      safeguards  of  body  against   .......        36 

44      settling  of,  in-doors   ........        22 

44      significance  of,  in  causing  disease  ......        50 

44      sweeping  away  of,  by  ciliated  cells  .....        39 

44     street-,  dangers  of  infection  from    .....  75 

"      tenacious  clinging  of,  to  fabrics       ......        29 

44      tobacco-  .........          5 

44      tubercle  bacilli  in 66 

44      two  modes  of  freeing  air  from          ......       102 

44     woollen  .  .  , f 

Dusting          •••••...•.78 

Erysipelas      .'»••••••••        55 

Evolution,  failure  of,  to  eliminate  the  porcine  element  in  street  loafers         .      100 
Expectoration  as  a  common  vice       .        •  •  •  •  •  .        99 

dangers  of,  in  consumptives          .  .  •  •  .        61 

Eyes,  harmful  effects  of  dust  on    .  .  .  .  .  .  .52 

Filters,  air-,  in  biological  air  analysis        .  .  .  .  •  .  13-15 

44       dust-,  lymph-glands  in  lungs  as  .  .  .  .  •  •        46 

Filthy  cities,  no  necessity  for         .            .  .  .  •  •  .92 

Filtration  method  of  air  analysis  .           .  .  ,  •  .  15 

General  knowledge,  necessary  to  prevent  spread  of  bacterial  diseases  by  dust       91 
Germs,  agrial  modes  of  study  of    .  .  .  .  •   "-     •  .11-13 


INDEX.  in 


PAGE 

Germs  in  in-doors  dust        ........        27 

44      in  out-doors  dust     ........        20 

44      colonies  of     .  .  .  .  .  .  .  .  .12 

"      nature  of.  ........          7 

"      origin  of,  in  in-doors  air     .  .  .  .  .  .  .30 

11       safeguards  of  body  against  aerial  .  .  .  .  .        36 

Hotel  bedrooms  as  sources  of  dust-infection        .....        91 
House  furnishing  as  affecting  the  risk  of  dust-infection  .  .  .78 

Immunity  of  body  to  disease  germs  ......        49 

In-doors  air,  analysis  of      ........  27-35 

Infection,  dangers  of,  from  street  dust     ......        75 

44          degrees  of  readiness  of,  in  different  diseases  .  .  .96 

Infectious  diseases    ........  •        55 

"        remedial  agents  in  .  .  .  .  .98 

Influenza        .  .  .  .  .  .  .  .  55,  56,  88 

Isolation  of  the  sick  as  means  of  prevention  of  bacterial  diseases        .  .54 

Lungs,  most  common  seat  of  tuberculosis  ....  -65 

pigmentation  of,  by  inhaled  dust  .....        44 

Lymph,  nitration  of,  in  the  lungs  ......        45 

Lymph-glands  as  dust-filters         .......        46 

44        **         localized  tuberculosis  in  .  .  .  .  .  .67 

Measles 55,96 

Meat,  tubercular,  as  food,  dangers  of  .  .  .  .  .64 

Michigan,  frequency  of  consumption  as  compared  with  small-pox  in  .        62 

Micro-organisms  in  in-doors  dust  .......        27 

44         <4  out-doors  dust  ......        20 

*4        nature  of  .  .  ......          7 

44  "        safeguards  of  body  against        .  .  .  .  .        36 

Milk  from  diseased  cows,  dangers  of          ......        64 

Motes  in  the  sunbeam          ........          3 

Moulds 7 

Mould-spores  in  air  analysis  .......        18 

"  "       il  dust 9 

41      preponderance  of,  in  wet  weather  .  .  .  .22 

Neumann,  air  analysis  by  .  .  .  .  .  .  .  •        33 

New  York,  air  analysis  in  .  .  .  .  .  .  .  .  23-26 

Official  negligence  no  excuse  for  private  indifference  to  cleanliness  .  .92 


I  1 2  INDEX. 


PAGE 

Petri's  air  analysis    ...•..•..23 
Phagocysts    .........        40-42,  48 

Phlegm,  removal  of,  by  ciliated  cells        ......        40 

Plate  method  of  air  analysis  .......  15-18 

Pneumonia     .........        55-56,  88 

Predisposition  to  consumption        .......        59 

Preventable  diseases  .  .  .  .  .  •  •  .        54 

Prevention  of  disease,  a  public  and  private  duty  •    •  .  .90 

"        "        **        more  reasonable  than  neglect  and  attempts  to  cure     .        98 

Public  conveyances  as  sources  of  danger  from  infectious  dust  *  .84 

Railway  carriages  as  sources  of  danger  from  dust  .  .  -       •  .        85 

Rain,  effects  of,  on  number  of  aerial  germs          .  .  •  «  .22 

Reinfection  of  tubercular  persons  by  expectoration  .  •  •  .      104 

Rooms  as  repositories  of  dust  and  germs  .            •  •  •  •  .        29 

Safeguards  of  body  against  dust  and  germs        .  •  .  .  .  36,  75 

Sanitariums  for  consumptives        «  ,  «  •  •  .  .      104 

Scarlatina       .  .  .  .  .  .  .  •         .  .  .  55, 96 

School-rooms,  dust  in          .  .  .  .  •  .  .  .84 

Sleeping-cars  as  sources  of  infection         •  •  •  .  .  .        86 

Small-pox       .  .  •  *  .  *  .  .  .       52,  62,  96 

Smoke,  ill  effects  of .  »  ,  .  .  .  .  .52 

Sneezing,  infective  spray  in  »  .  .  .  .  .  .77,87 

Snow,  effects  of,  on  aerial  germs  .......        22 

Spitting-cups  for  consumptives      .......        71 

Spitting,  dangerous  and  filthy  nature  of  .  .  .  .  .  .  72, 99 

Sputum,  dangerous  nature  of,  in  consumption  .  .  .  .  60,  66 

"        proper  means  of  disposing  of,  in  consumption  .  .  .71 

Steamships,  state-rooms  of,  as  sources  of  danger  .  .  .  .86 

Stein,  experiments  of,  on  floating  dust     ......        28 

Subways,  dust  in.  .  .  .  .  .  .  .  .86 

Sunlight,  action  of    .  .  .  .  .  .  .  64,  75,  97 

Sweeping,  effects  of,  on  aerial  germs  in  rooms  ....        3X~33»  79 

Theatres,  dusty,  dangers  of,  .  »  .  .  .  .  .81 

"  vicious  methods  of  cleaning  of  .  «...  82 

Tubercle  bacilli         .........  48 

"  "  growth  of,  in  the  body  only  under  favorable  conditions  .  97 

"  habitat  of.  64 

**            "        how  spread  in  the  air    .            .            .            .            .            .  64 

**  "  in  dusty  rooms  occupied  by  consumptives  ...  66 


INDEX.  \  1 3 


PAGE 

Tubercle  bacilli  in  expectoration  in  tuberculosis  of  lungs        ...        60 
"  "         »»  the  bodies  of  apparently  healthy  persons  ...        67 

mode  of  action  in  causing  consumption  .  .  .60 

not  easily  killed  by  drying  .  •  •        65 

spread  of,  by  diseased  meat  and  bad  milk      .  .  .64 

the  sole  direct  cause  of  consumption  .  .  59 

vulnerability  of,  when  growing  with  other  germs    .  .        64 

Tuberculoss 55*  5$ 

"  bacilli  of,  mode  of  action  in  causing          ....        6° 

"  frequency  and  mortality  of  .  .  .  «  .  61, 62 

••  heredity  of 59 

"  in  other  parts  of  the  body  than  the  lungs  .  .60 

"  localized 67 

M  mode  of  transmission  of  .  .  •  •  64 

41  predisposition  to  .  •  «  •  •  •        59 

"  spread  of,  by  meat  and  milk  .  .  •  •  .64 

*  M      ii     *»    dust    .......        58 

Tucker,  air  analysis  by        .  .  .  .  •  •  •  •  23i  31 

Typhoid  fever 55 

Vacuum  Cleaners      .........        79 

Ventilation,  effects  of,  on  floating  dust     ......        28 

Vigilance  necessary  to  prevent  spread  of  bacterial  diseases      .  .  .90 

Webster's  definition  of  dust  .......          3 

Wind,  effects  of,  on  floating  dust  and  germs        .  .  .  .  .        «a 

Yeasts 7 

Yellow  fever. & 


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